JavaScript - Image Map


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You can use JavaScript to create client-side image map. Client-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 clickable 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 clickable 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.



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