I have a pop up calendar that I use to populate txtBidOpenDate.Text. This works fine. What I'd like to do is populate a second textbox with a date that is seven days greater. I'm using the code below, which works fine. The problem is, I'd like the textbox to populate right away and not wait for a post back? Any Suggestions?

txtIntDisEndDate.Text = DateAdd(DateInterval.Day, 7, CDate(txtBidOpenDate.Text))