How to use Javascript to get elements by its class names
Get element by class name
getElementsByClassName(<class>) gets
the elements by class and returns HTMLElement[].
Example
<!DOCTYPE HTML>
<html>
<body>
<p class="myClass">myClass </p>
<p class="myClass anotherClass">two classes </p>
<script>
var elems = document.getElementsByClassName("myClass");
document.writeln(elems.length );
</script>
</body>
</html><!--from w w w. java 2 s .c om-->