Sorry, I&#039;m kind of a novice. <BR><BR>Im trying to replicate a classic 1st dropdown choice determines population of 2nd dropdown box. To do this, I created 2 dropdownboxes, the first of which has AutoPostBack="true" and OnSelectedIndexChange="popNumberTwo". The first box populates normally, but when I select an item, I get a *client-side* error stating Object does not support this property. It appears to direct me to the script automatically generated by - _doPostBack. <BR><BR>I&#039;m using a code-behind page for populating and to contain the popNumberTwo function. I have been able to get an otherwise blank page to perform autopostback without a problem, but when I try to apply it to a page (into which Ive put a lot of time, so I dont want to have to recreate it), I get the error above. Has anyone seen this before?<BR><BR>Thanks for any help<BR>