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Javascript - Image Map
  • 时间：2024-11-05

JavaScript - Image Map

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You can use JavaScript to create cpent-side image map. Cpent-side image maps are enabled by the usemap attribute for the <img /> tag and defined by special <map> and <area> extension tags.

The image that is going to form the map is inserted into the page using the <img /> element as normal, except that it carries an extra attribute called usemap. The value of the usemap attribute is the value of the name attribute on the <map> element, which you are about to meet, preceded by a pound or hash sign.

The <map> element actually creates the map for the image and usually follows directly after the <img /> element. It acts as a container for the <area /> elements that actually define the cpckable hotspots. The <map> element carries only one attribute, the name attribute, which is the name that identifies the map. This is how the <img /> element knows which <map> element to use.

The <area> element specifies the shape and the coordinates that define the boundaries of each cpckable hotspot.

The following code combines imagemaps and JavaScript to produce a message in a text box when the mouse is moved over different parts of an image.

<html>   
   <head>
      <title>Using JavaScript Image Map</title>
      
      <script type = "text/javascript">
         <!--
            function showTutorial(name) {
               document.myform.stage.value = name
            }
         //-->
      </script>
   </head>
   
   <body>
      <form name = "myform">
         <input type = "text" name = "stage" size = "20" />
      </form>
      
      <!-- Create  Mappings -->
      <img src = "/images/usemap.gif" alt = "HTML Map" border = "0" usemap = "#tutorials"/>
      
      <map name = "tutorials">
         <area shape="poly" 
            coords = "74,0,113,29,98,72,52,72,38,27"
            href = "/perl/index.htm" alt = "Perl Tutorial"
            target = "_self" 
            onMouseOver = "showTutorial( perl )" 
            onMouseOut = "showTutorial(  )"/>
         
         <area shape = "rect" 
            coords = "22,83,126,125"
            href = "/html/index.htm" alt = "HTML Tutorial" 
            target = "_self" 
            onMouseOver = "showTutorial( html )" 
            onMouseOut = "showTutorial(  )"/>
         
         <area shape = "circle" 
            coords = "73,168,32"
            href = "/php/index.htm" alt = "PHP Tutorial"
            target = "_self" 
            onMouseOver = "showTutorial( php )" 
            onMouseOut = "showTutorial(  )"/>
      </map>
   </body>
</html>

Output

You can feel the map concept by placing the mouse cursor on the image object.