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Why doesn't Javascript recognize the HTML class attribute?

Answer 1

+2 A:

Also you forgot braces after for(var i=0,j=els.length; i<j; i++) and alert("Class: " + els[i].className);.

MeF Corvi 2010-05-03 22:50:59

Seems like I've been working with Python too much lately :) Thank you!

Ilya Kogan 2010-05-04 02:52:12

Answer 2

+2 A:

This works just fine:

<html>
<head>
    <script type="text/javascript">
        function showElementClasses(node)  
        {

            alert("hello, world.");        
            var els = node.getElementsByTagName("*");
            for(var i=0,j=els.length; i<j; i++)
            {
                alert(els[i].getAttribute("class"));
                alert("Class: " + els[i].className);
            }
        }


    </script>
</head>
<body class="bla" onload="showElementClasses(document)">
    <div class="myclass" style="width: 500; height: 400" id="map" ></div>
</body>
</html>

Nitrodist 2010-05-03 22:54:04

Thank you so much! Why does it only work if the call is put into the onload attribute? Is the <script> executed before the <body> is even created?

Ilya Kogan 2010-05-04 02:38:54

Putting the call in the onload for the body tag insures that all of the tags in the entire document are loaded before you try to 'getElementsByTagName' for that document (unless you have elements AFTER the body tag ends, which isn't likely) since the body tag is the last tag in the document. Yes, you're correct, the script call is executed as soon as the line is parsed inside the script call so it's going to cause some problems for that method.

Nitrodist 2010-05-05 00:25:56

Answer 3

+1 A:

The only problem is that your alert("Class: " + els[i].className); statement is not being run inside your for loop. You need to correct your braces.

webdestroya 2010-05-03 23:03:27

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Why doesn't Javascript recognize the HTML class attribute?

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