How to enable/disable form elements using js onChange event of dropdownlist


I am stuck with a very simple thing.

I have a form with some textfields and dropdownlist in it. I want to enable/disable few form elements(textfields and dropdownlist) depending on the selected value of a dropdownlist. In the onchange event of dropdownlist i call a javascript function which depending on the value selected should enable/disable the form elements. Now my problem is i am not able to address the form elements in the js function. For example Normally in HTML/js we use document.formname.elementname.disable=true to disable a particular element. How do i do it here?

Please help me.


I also tried $(’#elementname’).(‘disabled’,false) but its not working.

Please help anyone.