filling in a textbox

[wxdqz]

I need to fill in a textbox with a date of one day greater then the date the user puts in another textbox. The textbox can also stay empty, so I'll need to check if data was placed in. I'm writing this in ASP.NET, the code below works fine to add a date one day greater then what the user selected, but I need to place it in a javascript, so the code runs on the client side...I'm new to javascript, can some give me an example....thanks





'txtIntDisEndDate.Text = DateAdd(DateInterval.Day, 1, CDate(txtBidOpenDate.Text))