Question

I’ve spent over three hours on this trying to work with the code I’ve been given. I’ve never done javascript. Please help.
I have a form with 4 radio buttons, one specifying “other” and next to a text box that is supposed to post the user specified value. Here’s what I’ve tried.
HTML:

<td id="amount_container">
    <input name="chargetotal" type="radio" value="75.00" onclick="donation_value();" />$75<br />
    <input name="chargetotal" type="radio" value="125.00" onclick="donation_value();" />$125<br />
    <input name="chargetotal" type="radio" value="250.00" onclick="donation_value();" />$250<br />
    <input name="chargetotal" type="radio" value="other" />other
    <input type="text" name="specified" size="10" />
</td>  

javascript:

<script type="text/javascript">
function donation_value(){
    var val = 0;
    for( i = 0; i < document.form1.chargetotal.length; i++ ) {
        if( document.form1.chargetotal[i].checked == true ) {
            val = document.form1.chargetotal[i].value;
            if(val=='other') {
                document.form1.specified.disabled=false;
                document.form1.specified.focus();
                document.form1.chargetotal.value=document.form1.specified.value;
            } else {
                document.form1.specified.disabled=true;
            }
        }
    }
}
</script>

Answer 1

It seems, you forgot to add onclick handler to “other” radio.
I think it should be

<input name="chargetotal" type="radio" value="other" onclick="donation_value();"/>

Update

I think I understood what your problem is 🙂
You can add callback, whick will be invoked when page is submitted. This callback will set value for “other” radio if it is selected. Something like

function assignOtherValue() {
    for( i = 0; i < document.form1.chargetotal.length; i++ ) {
        if( document.form1.chargetotal[i].checked == true ) {
            var val = document.form1.chargetotal[i].value;
            if(val=='other') {
                document.form1.chargetotal[i].value=document.form1.specified.value;
            }
        }
    }
    return true;
}

And add to form:

<form name="form1" onSubmit="return assignOtherValue();">