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Editorial Team
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Asked: 2026-05-16T13:54:08+00:00

I’m processing a form with php and I want to add validation on the

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I’m processing a form with php and I want to add validation on the client side too. I read about.com’s tutorial about validating radio buttons with javascript and set up this sample according to its guidelines.

a) Why isn’t it showing the alert message?

b) How can I substitute the alert message for some innerHtml text? 

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html><head>

<meta content="text/html; charset=ISO-8859-1" http-equiv="content-type"><title>validateradio</title>


<script type="text/javascript">


function valButton(btn) {
    var cnt = -1;
    for (var i=btn.length-1; i > -1; i--) {
        if (btn[i].checked) {cnt = i; i = -1;}
    }
    if (cnt > -1)  return btn[cnt].value;
    else          return null;

}




function valButton2(form){

var btn=valButton(form.group1);
if (btn==null){alert('no radio button selected');}
else alert('button value' + btn + 'selected');


}


</script>


</head>


<body style="color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);" alink="#000088" link="#0000ff" vlink="#ff0000"><br>

<form name="myform">


 <label for="r1"><input type="radio"
name="group1" id="r1" value="1" /> button one</label> 

 <label for="r2"><input type="radio"
name="group1" id="r2" value="2" /> button two</label>

 <label for="r3"><input type="radio"
name="group1" id="r3" value="3" /> button three</label> 


<input type="submit" name="submitit" onclick="valbutton2(myform);" value="Validate" />



</form>



</body></html>
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1 Answer

  1. Editorial Team

    Looks like a case issue. Your onclick handler for the submit button is valbutton2(myform); but the name of the function you are trying to call is actually valButton2.

    With regards to getting the innerHTML, without using a framework it can be kind of ugly. One solution would be to add an id to the labels that contains the id of the corresponding radio button:

    <label for="r1" id="lbl-r1"><input type="radio" name="group1" id="r1" value="1" /> button one</label>

    Then return a reference to the selected radio button from your second function instead of its value return btn[cnt]; instead of return btn[cnt].value;. Then you could access the label text using something like the following:

    var id = btn.getAttribute("id");
var lbl = document.getElementById("lbl-" + id);
for (var i = 0; i < lbl.childNodes.length; i++) {
    var n = lbl.childNodes[i];
    if (n.nodeType == 3) {
        alert(n.nodeValue);
    }
}

    I’ve been using jQuery and other frameworks for so long now I’m more than a little rusty at doing this in straight javascript, so this could probably be improved a lot, but you get the idea.

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