Javascript for modal window

Im sure this is prolly an easy question for you guru folk

Does anyone have example JS code of how to keep a window modal ? I am popping up a box in which the person needs to enter a date. I would like this window to never lose focus until the user either answers it or presses cancel.... I would like to avoid using an alert box... Anyone?
thanks in advance all..

var date = window.prompt("Enter a date:");

Hey there

IE4+ supports the showModalDialog method - this enables you to use an HTML document as your modal window.

You can read all about that method here:

http://msdn.microsoft.com/workshop/...ModalDialog.asp

In the body tag, specify the onBlur attribute with "self.focus()" as its value.