Looping through Form Elements?

[altergothen]

Hi there

I have a form with elements named (& id) 1 through 5
Why can't I loop through all my form elements like this...

function toggle(){
	for (var i=1;i<=5;i++)
	{
		var y = document.getElementById(i);
		y.style.backgroundColor = '#FFFFFF';		

	}
}

The error I get is y is null???
If I hard code the id's like this...
var y = document.getElementById('2');
it works fine??

Please Help

NEWB

[abduraooft]

var y = document.getElementById(i);

Validate your markup first. You can't have the value of an id that starts with a number.

[Philip M]

Form names and ids may not start with a digit.

Try this:-

<form name = "myform">
<input name="Field1" type="text" /><br>
<input name="Field2" type="text" /><br>
<input name="Field3" type="text" /><br>
<input name="Field4" type="text" /><br>
<input name="Field5" type="text" /><br>
<input type = button value = "Change Background Color" onclick = "chk()">
</form>

<script type = "text/javascript">
function chk() {
for(var i=1; i<=5; i++){
document["myform"]["Field" + i].style.backgroundColor = '#FF0000';		
}
}
</script>

or if you want to use ids:-

<script type = "text/javascript">
function chk() {
for(var i=1; i<=5; i++){
document.getElementById("Field" + i).style.backgroundColor = '#FF0000';		
}
}
</script>

Originally Posted by altergothen

The error I get is y is null???
If I hard code the id's like this...
var y = document.getElementById('2');
it works fine??

Yes it does, because '2' is a string value, not a number. But very srongly advised to avoid.

Nothing's black or white in our country - you're either brilliant or you're hopeless. - Commentator, Radio 5 Live

[DrDOS]

That's because when you hard code it 2 is a string and not a number. Better to not use numbers as IDs or names, try this:

function toggle(){
	for (var i=1;i<=5;i++)
	{
		var y = document.getElementById("form_item"+i);
		y.style.backgroundColor = '#FFFFFF';		

	}
}

where the names and IDs are form_item1, etc., of course you can use any text string you want.

[altergothen]

Thanks Guys!!!
you have been a great help ;-)