<head>
<script language="javascript">
function readCheckbox(){
var myChkArray=document.getElementsByName("myCheckbox"); //get all the
//elements with name "myCheckbox"
for(var i=0; i<myChkArray.length; i++){
if(myChkArray[i].checked)//returns true if checkbox is checked
alert(myChkArray[i].value);
}
}
</script>
</head>
<body>
<div>
<input type="checkbox" name="myCheckbox" value="one"/>one
<input type="checkbox" name="myCheckbox" value="two"/>two
<input type="checkbox" name="myCheckbox" value="three"/>three
<br/>
<input type="button" onclick="readCheckbox();"/>
</div>
</body>
</html>