I can't get the

function getchecked() to show

an alert box...

Code:
<script>
function getCheckedValue(radioObj) {
	if(!radioObj){
		return "";
       }
	var radioLength = radioObj.length;
	if(radioLength == undefined){
		if(radioObj.checked){
			return radioObj.value;
		}else{
			return "";
                }
        }
	for(var i = 0; i < radioLength; i++) {
		if(radioObj[i].checked) {
			return radioObj[i].value;
		}
	}
	return "";
}
}
function getchecked(){
var thecode=getCheckedValue(document.forms['radioExampleForm'].elements['code']);
if(thecode!==""){
if(thecode=="HTML"){
alert('Checked value is: '+thecode+'.');
//playSound("test1.mp3");
}else if(thecode=="PHP"){
//playSound("test2.mp3");
alert('Checked value is: '+thecode+'.');
}else{
//playSound("test3.mp3");
alert('Checked value is: nothing');
}
}
}
</script>

<label for="code1"><input type="radio" value="HTML" name="code" id="code1"> HTML</label>
<br><label for="code2"><input type="radio" value="PHP" name="code" id="code2"> PHP</label>
<br><label for="code3"><input type="radio" value="MySQL" name="code" id="code3"> MySQL</label>
<br><input type="button" onclick="getchecked()" value="Show Checked Value">
thanks!