i have a checkboxlist and a checkbox control. When the user selects the checkbox, it unchecks all selected items in the checkboxlist and alternatively if any item on the checkboxlist is selected, then it unchecks checkbox. I can accomplish this in code but this also requires that the controls postback each time. The page has several of these controls so my main goal really is to accomplish the process without posting back the page each time a control is clicked. I'll try your solution, I have a javascript function that runs if added to the checkbox through the html but the asp checkboxlist doesn't have this attribute.