Disabling a field in java script

[Vijayalakshmi Karthikeyan]

I have a dynamic page
I just want to disable a field based on a selection of combo box..

Here is my code

var wc=document.getElementsByName("rows[0].columns[2].columnValue");
	alert(wc[0].disabled);
	wc[0].disabled=true;
	alert(wc[0].disabled);

On the view source-->

<input type="text" name="rows[0].columns[2].columnValue" maxlength="8" value="" onchange="onChangeWrapper(alwaysGood(this))" readonly="readonly">

But it is not working. 1st alert gives me false and second alert gives me true. But on the page it is not disabled.

Can any one guide me

[Bear Bibeault]

Why all the complicated referencing? Just give the element an id value, and use the id with document.getElementById().

[Eric Pascarello]

Not sure what you combo box is, but is it causing the page to post back or something which is resetting the page?

[Vijayalakshmi Karthikeyan]

Hi .
Am very sorry for late reply.
The form was fully dynamic and they were using some inner HTML.
Mistake was on my side. I have given wrong name. I found and corrected it.
Thank you all. .