Select corresponding radio button by value

I set a (var rbtVal) in global and would like to automatically check
the corresponding radio button in the form onLoad

smtng like:
function setRbtEcho()
{
  var thisRbtn;

for (i=0;i<3;i++)
{
//I don't know how to loop trough the getElementById for radio buttons
if (document.getElementById('myRadioButtonEcho'[i]).value = rbtVal)
    {document.getElementById('myRadioButtonEcho'[i]).checked;}

 }

<body onLoad="setRbtEcho();">
<form>
<input type="radiobutton" id="myRadioButtonEcho" value="2b">
<input type="radiobutton" id="myRadioButtonEcho" value="3c">
<input type="radiobutton" id="myRadioButtonEcho" value="4e">
</form>
</dody>
JoeUSAsked:
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MorcalavinCommented:
You can't loop through getElementById, because only one element is allowed to have it at a time.  It's unique.  You need something like getElementByTagName.  You could also youse getElementsByName.  It depends on if you want the radio buttons to have the same name(grouping) or not.

<script>
function setRbtEcho() {
var rbtVal = '3c';
inputs = document.getElementsByTagName('input');
for(var i=0; i < inputs.length; i++) {
        if(inputs[i].type == 'radio') {
               if(inputs[i].value == rbtVal) {
                        inputs[i].checked = true;
                }
        }
}
}
</script>

<body onLoad="setRbtEcho();">
<form>
<input type="radio" id="myRadioButtonEcho" value="2b">
<input type="radio" id="myRadioButtonEcho" value="3c">
<input type="radio" id="myRadioButtonEcho" value="4e">
</form>
</body>
0

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JoeUSAuthor Commented:
Fantastic!

Thanks a lot for the info on the getElementById and for the example.
I ended up using the getElementsByName
0
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