change text box value according to another text box

kevpho · Jul 5, 2004

Hi there,

I've been trying to update the value of one textbox by using the onChange event when another textbox is modified. For now, I just want it to work so I'm trying to copy the exact value without any calculation, but for some reason it's not working. I suppose there's something wrong with my syntax, but I can't find it out. Here's the code:

Code:

<script language="Javascript">
<!--
	function updateX4(original)
	{
//The value of the field to update is always just 1 more than the incoming original variable		
var toChange = new String(parseInt(original.name) + 1);
		document.forms['pay'][toChange].value = original.value;
	}
-->
</script>

<form name="pay" action="paycreate.asp" method="post">
<input type="text" name="1000" onChange="updateX4(this)">
<input type="text" name="1001">
</form>

This is just an example, but my page uses asp and creates a number of form fields so the names will vary. The error is somewhere in the "document.forms['paysheet']....." line but I've tried many different combinations and keep getting an object expected error. If I just use alerts all the numbers I want are passed properly into and throughout the function.

Any help would be greatly appreciated. Thanks!

Kevin

BillyRayPreachersSon · Jul 5, 2004

It is your (illegal) use of form element names beginning with numbers that it causing the problem. Names should never begin with numbers. Changing them to something like "n1000", "n1001", etc, and then modifying your code to something like this:

Code:

<html>
<head>
<script language="Javascript">
<!--
	function updateX4(original) {
		//The value of the field to update is always just 1 more than the incoming original variable
		var toChange = parseInt(original.name.slice(1), 10) + 1;
        document.forms['pay']['n' + toChange].value = original.value;
	}
//-->
</script>
</head>
<body>
<form name="pay" action="paycreate.asp" method="post">
<input type="text" name="n1000" onChange="updateX4(this)">
<input type="text" name="n1001">
</form>
</body>
</html>

works for me.

Hope this helps,
Dan

kevpho · Jul 5, 2004

Hi Dan,

Thanks for your help. I didn't realize that I was using illegal form names. Works just fine now.

Kevin

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change text box value according to another text box

kevpho

Programmer

BillyRayPreachersSon

Programmer

kevpho

Programmer

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