JavaScript RegExp Tutorial
Selected Reading
- JavaScript RegExp - Discussion
- JavaScript RegExp - Useful Resources
- JavaScript RegExp - Quick Guide
- JavaScript RegExp - toString()
- JavaScript RegExp - toSource()
- JavaScript RegExp - test()
- JavaScript RegExp - exec()
- JavaScript RegExp - source
- JavaScript RegExp - multiline
- JavaScript RegExp - lastIndex
- JavaScript RegExp - ignoreCase
- JavaScript RegExp - global
- JavaScript RegExp - constructor
- JavaScript RegExp - g
- JavaScript RegExp - i
- JavaScript RegExp - (foo|bar|baz)
- JavaScript RegExp - [^aeiou]
- JavaScript RegExp - [aeiou]
- JavaScript RegExp - W
- JavaScript RegExp - w
- JavaScript RegExp - D
- JavaScript RegExp - d
- JavaScript RegExp - S
- JavaScript RegExp - s
- JavaScript RegExp - .
- JavaScript RegExp - uxxxx
- JavaScript RegExp - xnn
- JavaScript RegExp -
- JavaScript RegExp - f
- JavaScript RegExp - v
- JavaScript RegExp -
- JavaScript RegExp -
- JavaScript RegExp -
- JavaScript RegExp - Alphanumeric
- JavaScript RegExp - p(hp)*
- JavaScript RegExp - <b>(.*)</b>
- JavaScript RegExp - ^.{2}$
- JavaScript RegExp - p.p
- JavaScript RegExp - [^a-zA-Z]
- JavaScript RegExp - ^p
- JavaScript RegExp - p$
- JavaScript RegExp - p{N,}
- JavaScript RegExp - p{N1,N2}
- JavaScript RegExp - p{N}
- JavaScript RegExp - p?
- JavaScript RegExp - p*
- JavaScript RegExp - p+
- JavaScript RegExp - [a-zA-Z]
- JavaScript RegExp - [A-Z]
- JavaScript RegExp - [a-z]
- JavaScript RegExp - [0-9]
- JavaScript RegExp - [^...]
- JavaScript RegExp - [...]
- JavaScript RegExp - Overview
- JavaScript RegExp - Home
Selected Reading
- Who is Who
- Computer Glossary
- HR Interview Questions
- Effective Resume Writing
- Questions and Answers
- UPSC IAS Exams Notes
JavaScript RegExp - Quick Guide
JavaScript RegExp - Quick Guide
JavaScript RegExp - Overview
A regular expression is an object that describes a pattern of characters.
The JavaScript RegExp class represents regular expressions, and both String and RegExp define methods that use regular expressions to perform powerful pattern-matching and search-and-replace functions on text.
Syntax
A regular expression could be defined with the RegExp () constructor, as follows −
var pattern = new RegExp(pattern, attributes); or simply var pattern = /pattern/attributes;
Here is the description of the parameters −
pattern − A string that specifies the pattern of the regular expression or another regular expression.
attributes − An optional string containing any of the "g", "i", and "m" attributes that specify global, case-insensitive, and multi-pne matches, respectively.
Example
Following example shows usage of RegExp to check if a string is present in given text or not.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "Javascript is an interesting scripting language";
var re = new RegExp( "script", "g" );
var result = re.test(str);
document.write("Test 1 - returned value : " + result);
re = new RegExp( "pushing", "g" );
var result = re.test(str);
document.write("<br />Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : true Test 2 - returned value : false
JavaScript RegExp - [...]
Description
[...] checks if any one character between the brackets is present in the searched string.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "first";
var pattern = /[abcde]/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "second";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : null Test 2 - returned value : e,c,d
JavaScript RegExp - [^...]
Description
[^...] checks if any one character between the brackets is not present in the searched string.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "first";
var pattern = /[^abcde]/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "second";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : f,i,r,s,t Test 2 - returned value : s,o,n
JavaScript RegExp - [0-9]
Description
[0-9] matches any decimal digit from 0 through 9.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "first";
var pattern = /[0-9]/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "2nd";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : null Test 2 - returned value : 2
JavaScript RegExp - [a-z]
Description
[a-z] matches any character from lowercase a through lowercase z.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "first";
var pattern = /[a-z]/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "Second";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : f,i,r,s,t Test 2 - returned value : e,c,o,n,d
JavaScript RegExp - [A-Z]
Description
[A-Z] matches any character from uppercase A through uppercase Z.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "first";
var pattern = /[A-Z]/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "Second";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : null Test 2 - returned value : S
JavaScript RegExp - [a-zA-Z]
Description
[a-zA-Z] matches any character from lowercase a through uppercase Z.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "first1";
var pattern = /[a-zA-Z]/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "Second2";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : f,i,r,s,t Test 2 - returned value : S,e,c,o,n,d
JavaScript RegExp - p+
Description
p+ matches any string containing one or more p s.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abcpp";
var pattern = /p+/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : pp Test 2 - returned value : null
JavaScript RegExp - p*
Description
p* matches any string containing zero or more p s.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abcpp";
var pattern = /p*/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : ,,,pp, Test 2 - returned value : ,,,
JavaScript RegExp - p?
Description
p? matches any string containing zero or more p s.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abcpp";
var pattern = /p?/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : ,,,p,p, Test 2 - returned value : ,,,
JavaScript RegExp - p{N}
Description
p{N} matches any string containing a sequence of N p s.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abcpp";
var pattern = /p{2}/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abcp";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : pp Test 2 - returned value : null
JavaScript RegExp - p{N1, N2}
Description
p{N1, N2} matches any string containing a sequence of N1 or N2 p s.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abcpp";
var pattern = /p{2,3}/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abcp";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : pp Test 2 - returned value : null
JavaScript RegExp - p{N,}
Description
p{N,} matches any string containing at least a sequence of N p s.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abcpp";
var pattern = /p{2,}/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abcp";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : pp Test 2 - returned value : null
JavaScript RegExp - p$
Description
p$ matches any string containing p at the end of it.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abcpp";
var pattern = /p$/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : p Test 2 - returned value : null
JavaScript RegExp - ^p
Description
^p matches any string containing p at the start of it.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "pabc";
var pattern = /^p/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : p Test 2 - returned value : null
JavaScript RegExp - [^a-zA-Z]
Description
[^a-zA-Z] matches any string not containing any of the characters ranging from a through z and A through Z.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "1323pabc";
var pattern = /[^a-zA-Z]/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : 1,3,2,3 Test 2 - returned value : null
JavaScript RegExp - p.p
Description
p.p matches any string containing p, followed by any character, in turn followed by another p.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "pap";
var pattern = /p.p/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "pp";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : pap Test 2 - returned value : null
JavaScript RegExp - ^.{2}$
Description
^.{2}$ matches any string containing exactly two characters.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "pa";
var pattern = /^.{2}$/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "pap";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : pa Test 2 - returned value : null
JavaScript RegExp - <b>(.*)</b>
Description
<b>(.*)</b> matches any string enclosed within <b> and </b>.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "<b>ab</b>";
var pattern = /<b>(.*)</b>/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "pap";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : ab Test 2 - returned value : null
JavaScript RegExp - p(hp)*
Description
p(hp)* matches any string containing a p followed by zero or more instances of the sequence hp.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "phphp";
var pattern = /p(hp)*/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "pap";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : phphp Test 2 - returned value : p,p
JavaScript RegExp - Alphanumeric
Description
Alphanumeric matches itself.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab1";
var pattern = /abc/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : null Test 2 - returned value : abc
JavaScript RegExp -
Description
matches the NUL character (u0000).
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab c";
var pattern = / /g;
var index = str.search(pattern);
document.write("Test 1 - returned value : " + index);
str = "abc";
index = str.search(pattern);
document.write("<br/>Test 2 - returned value : " + index);
</script>
</body>
</html>
Output
Test 1 - returned value : 2 Test 2 - returned value : -1
JavaScript RegExp -
Description
matches the Tab character (u0009).
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab c";
var pattern = / /g;
var index = str.search(pattern);
document.write("Test 1 - returned value : " + index);
str = "abc";
index = str.search(pattern);
document.write("<br/>Test 2 - returned value : " + index);
</script>
</body>
</html>
Output
Test 1 - returned value : 2 Test 2 - returned value : -1
JavaScript RegExp -
Description
matches the New pne character (u00A).
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab
c";
var pattern = /
/g;
var index = str.search(pattern);
document.write("Test 1 - returned value : " + index);
str = "abc";
index = str.search(pattern);
document.write("<br/>Test 2 - returned value : " + index);
</script>
</body>
</html>
Output
Test 1 - returned value : 2 Test 2 - returned value : -1
JavaScript RegExp - v
Description
v matches the Vertical Tab character (u00B).
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abvc";
var pattern = /v/g;
var index = str.search(pattern);
document.write("Test 1 - returned value : " + index);
str = "abc";
index = str.search(pattern);
document.write("<br/>Test 2 - returned value : " + index);
</script>
</body>
</html>
Output
Test 1 - returned value : 2 Test 2 - returned value : -1
JavaScript RegExp - f
Description
f matches the formfeed character (u00C).
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abfc";
var pattern = /f/g;
var index = str.search(pattern);
document.write("Test 1 - returned value : " + index);
str = "abc";
index = str.search(pattern);
document.write("<br/>Test 2 - returned value : " + index);
</script>
</body>
</html>
Output
Test 1 - returned value : 2 Test 2 - returned value : -1
JavaScript RegExp -
Description
matches the Carriage return character (u00D).
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab
c";
var pattern = /
/g;
var index = str.search(pattern);
document.write("Test 1 - returned value : " + index);
str = "abc";
index = str.search(pattern);
document.write("<br/>Test 2 - returned value : " + index);
</script>
</body>
</html>
Output
Test 1 - returned value : 2 Test 2 - returned value : -1
JavaScript RegExp - xnn
Description
xnn matches the Latin character specified by the hexadecimal number nn; for example, x0A is the same as .
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abx0Ac";
var pattern = /x0A/g;
var index = str.search(pattern);
document.write("Test 1 - returned value : " + index);
str = "abc";
index = str.search(pattern);
document.write("<br/>Test 2 - returned value : " + index);
</script>
</body>
</html>
Output
Test 1 - returned value : 2 Test 2 - returned value : -1
JavaScript RegExp - uxxxx
Description
uxxxx matches the Unicode character specified by the hexadecimal number xxxx; for example, u0009 is the same as .
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abu0009c";
var pattern = /u0009/g;
var index = str.search(pattern);
document.write("Test 1 - returned value : " + index);
str = "abc";
index = str.search(pattern);
document.write("<br/>Test 2 - returned value : " + index);
</script>
</body>
</html>
Output
Test 1 - returned value : 2 Test 2 - returned value : -1
JavaScript RegExp - .
Description
. matches a single character.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abc";
var pattern = /./g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : a,b,c Test 2 - returned value : null
JavaScript RegExp - s
Description
s matches a whitespace character (space, tab, newpne).
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab c";
var pattern = /s/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : Test 2 - returned value : null
JavaScript RegExp - S
Description
S matches a non-whitespace character.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab c";
var pattern = /S/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : a,b,c Test 2 - returned value : null
JavaScript RegExp - d
Description
d matches a digit (0-9).
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab123c";
var pattern = /d/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : 1,2,3 Test 2 - returned value : null
JavaScript RegExp - D
Description
D matches a non-digit.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab123c";
var pattern = /D/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : a,b,c Test 2 - returned value : a,b,c
JavaScript RegExp - w
Description
w matches a word character (a-z, A-Z, 0-9, _).
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab123c_#@";
var pattern = /w/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc bcd";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : a,b,1,2,3,c,_ Test 2 - returned value : a,b,c,b,c,d
JavaScript RegExp - W
Description
w matches a non-word character.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "ab123c_#@";
var pattern = /W/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "abc bcd";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : #,@ Test 2 - returned value :
JavaScript RegExp - [aeiou]
Description
[aeiou] matches a single character in the given set.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "first alphabet";
var pattern = /[abcde]/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "second";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : a,a,b,e Test 2 - returned value : e,c,d
JavaScript RegExp - [^aeiou]
Description
[^aeiou] matches a single character outside the given set.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "first alphabet";
var pattern = /[^abcde]/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "second";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : f,i,r,s,t, ,l,p,h,t Test 2 - returned value : s,o,n
JavaScript RegExp - (foo|bar|baz)
Description
(foo|bar|baz) matches any of the alternatives specified.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "foo abc";
var pattern = /(foo|bar|baz)/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
str = "bar baz";
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : foo Test 2 - returned value : bar,baz
JavaScript RegExp - i
Description
i perform case-insensitive matching.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abcABC";
var pattern = /[aeiou]/ig;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
pattern = /[aeiou]/g;
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : a,A Test 2 - returned value : a
JavaScript RegExp - g
Description
g performs a global match that is, find all matches rather than stopping after the first match.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp</title>
</head>
<body>
<script type = "text/javascript">
var str = "abcabcabc";
var pattern = /abc/g;
var result = str.match(pattern);
document.write("Test 1 - returned value : " + result);
pattern = /abc/;
result = str.match(pattern);
document.write("<br/>Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : abc,abc,abc Test 2 - returned value : abc
JavaScript RegExp - constructor
Description
It returns a reference to the array function that created the instance s prototype.
Syntax
Its syntax is as follows −
RegExp.constructor
Return Value
Returns the function that created this object s instance.
Example
Following example shows usage of RegExp expression.
<html>
<head>
<title>JavaScript RegExp constructor Property</title>
</head>
<body>
<script type = "text/javascript">
var re = new RegExp( "string" );
document.write("re.constructor is:" + re.constructor);
</script>
</body>
</html>
Output
re.constructor is: function RegExp() { [native code] }
JavaScript RegExp - global
Description
global is a read-only boolean property of RegExp objects. It specifies whether a particular regular expression performs global matching, i.e., whether it was created with the "g" attribute.
Syntax
Its syntax is as follows −
RegExpObject.global
Return Value
Returns "TRUE" if the "g" modifier is set, "FALSE" otherwise.
Example
<html>
<head>
<title>JavaScript RegExp global Property</title>
</head>
<body>
<script type = "text/javascript">
var re = new RegExp( "string" );
if ( re.global ) {
document.write("Test1 - Global property is set");
} else {
document.write("Test1 - Global property is not set");
}
re = new RegExp( "string", "g" );
if ( re.global ) {
document.write("<br />Test2 - Global property is set");
} else {
document.write("<br />Test2 - Global property is not set");
}
</script>
</body>
</html>
Output
Test1 - Global property is not set Test2 - Global property is set
JavaScript RegExp - ignoreCase
Description
ignoreCase is a read-only boolean property of RegExp objects. It specifies whether a particular regular expression performs case-insensitive matching, i.e., whether it was created with the "i" attribute.
Syntax
Its syntax is as follows −
RegExpObject.ignoreCase
Return Value
Returns "TRUE" if the "i" modifier is set, "FALSE" otherwise.
Example
<html>
<head>
<title>JavaScript RegExp ignoreCase Property</title>
</head>
<body>
<script type = "text/javascript">
var re = new RegExp( "string" );
if ( re.ignoreCase ) {
document.write("Test1-ignoreCase property is set");
} else {
document.write("Test1-ignoreCase property is not set");
}
re = new RegExp( "string", "i" );
if ( re.ignoreCase ) {
document.write("<br/>Test2-ignoreCase property is set");
} else {
document.write("<br/>Test2-ignoreCase property is not set");
}
</script>
</body>
</html>
Output
Test1 - ignoreCase property is not set Test2 - ignoreCase property is set
JavaScript RegExp - lastIndex
Description
lastIndex a read/write property of RegExp objects. For regular expressions with the "g" attribute set, it contains an integer that specifies the character position immediately following the last match found by the RegExp.exec() and RegExp.test() methods. These methods use this property as the starting point for the next search they conduct.
This property allows you to call those methods repeatedly, to loop through all matches in a string and works only if the "g" modifier is set.
This property is read/write, so you can set it at any time to specify where in the target string, the next search should begin. exec() and test() automatically reset the lastIndex to 0 when they fail to find a match (or another match).
Syntax
Its syntax is as follows −
RegExpObject.lastIndex
Return Value
Returns an integer that specifies the character position immediately following the last match.
Example
<html>
<head>
<title>JavaScript RegExp lastIndex Property</title>
</head>
<body>
<script type = "text/javascript">
var str = "Javascript is an interesting scripting language";
var re = new RegExp( "script", "g" );
re.test(str);
document.write("Test 1 - Current Index: " + re.lastIndex);
re.test(str);
document.write("<br />Test 2 - Current Index: " + re.lastIndex);
</script>
</body>
</html>
Output
Test 1 - Current Index: 10 Test 2 - Current Index: 35
JavaScript RegExp - multipne
Description
multipne is a read-only boolean property of RegExp objects. It specifies whether a particular regular expression performs multipne matching, i.e., whether it was created with the "m" attribute.
Syntax
Its syntax is as follows −
RegExpObject.multipne
Return Value
Returns "TRUE" if the "m" modifier is set, "FALSE" otherwise.
Example
<html>
<head>
<title>JavaScript RegExp multipne Property</title>
</head>
<body>
<script type = "text/javascript">
var re = new RegExp( "string" );
if ( re.multipne ) {
document.write("Test1-multipne property is set");
} else {
document.write("Test1-multipne property is not set");
}
re = new RegExp( "string", "m" );
if ( re.multipne ) {
document.write("<br/>Test2-multipne property is set");
} else {
document.write("<br/>Test2-multipne property is not set");
}
</script>
</body>
</html>
Output
Test1 - multipne property is not set Test2 - multipne property is set
JavaScript RegExp - source
Description
source is a read-only string property of RegExp objects. It contains the text of the RegExp pattern. This text does not include the depmiting slashes used in regular-expression pterals, and it does not include the "g", "i", and "m" attributes.
Syntax
Its syntax is as follows −
RegExpObject.source
Return Value
Returns the text used for pattern matching.
Example
<html>
<head>
<title>JavaScript RegExp source Property</title>
</head>
<body>
<script type = "text/javascript">
var str = "Javascript is an interesting scripting language";
var re = new RegExp( "script", "g" );
re.test(str);
document.write("The regular expression is : " + re.source);
</script>
</body>
</html>
Output
The regular expression is : script
JavaScript RegExp - exec
Description
The exec method searches string for text that matches regexp. If it finds a match, it returns an array of results; otherwise, it returns null.
Syntax
Its syntax is as follows −
RegExpObject.exec( string );
Parameter Details
string − The string to be searched
Return Value
Returns the matched text if a match is found, and null if not.
Example
<html>
<head>
<title>JavaScript RegExp exec Method</title>
</head>
<body>
<script type = "text/javascript">
var str = "Javascript is an interesting scripting language";
var re = new RegExp( "script", "g" );
var result = re.exec(str);
document.write("Test 1 - returned value : " + result);
re = new RegExp( "pushing", "g" );
var result = re.exec(str);
document.write("<br />Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : script Test 2 - returned value : null
JavaScript RegExp - test
Description
The test method searches string for text that matches regexp. If it finds a match, it returns true; otherwise, it returns false.
Syntax
Its syntax is as follows −
RegExpObject.test( string );
Parameter Details
string − The string to be searched
Return Value
Returns the matched text if a match is found, and null if not.
Example
<html>
<head>
<title>JavaScript RegExp test Method</title>
</head>
<body>
<script type = "text/javascript">
var str = "Javascript is an interesting scripting language";
var re = new RegExp( "script", "g" );
var result = re.test(str);
document.write("Test 1 - returned value : " + result);
re = new RegExp( "pushing", "g" );
var result = re.test(str);
document.write("<br />Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : true Test 2 - returned value : false
JavaScript RegExp - toSource
Description
The toSource method string represents the source code of the object. This method does not work with all the browsers.
This method does not work with all the browsers.
Syntax
Its syntax is as follows −
RegExpObject.toSource();
Return Value
Returns the string representing the source code of the object.
Example
Try the following example program.
<html>
<head>
<title>JavaScript RegExp toSource Method</title>
</head>
<body>
<script type = "text/javascript">
var str = "Javascript is an interesting scripting language";
var re = new RegExp( "script", "g" );
var result = re.toSource(str);
document.write("Test 1 - returned value : " + result);
re = new RegExp( "/", "g" );
var result = re.toSource(str);
document.write("<br />Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : /script/g Test 2 - returned value : ///g
JavaScript RegExp - toString
Description
The toString method returns a string representation of a regular expression in the form of a regular-expression pteral.
Syntax
Its syntax is as follows −
RegExpObject.toString();
Return Value
Returns the string representation of a regular expression.
Example
<html>
<head>
<title>JavaScript RegExp toString Method</title>
</head>
<body>
<script type = "text/javascript">
var str = "Javascript is an interesting scripting language";
var re = new RegExp( "script", "g" );
var result = re.toString(str);
document.write("Test 1 - returned value : " + result);
re = new RegExp( "/", "g" );
var result = re.toString(str);
document.write("<br />Test 2 - returned value : " + result);
</script>
</body>
</html>
Output
Test 1 - returned value : /script/g Test 2 - returned value : ///gAdvertisements