Passing Textbox value form a Child Window to Parent Window Using JavaScript...

There are many a time when you might want to open a child window for showing a calendar and returning the selected value to the parent form text box,

Here's how to do it using JavaScript.

Open the HTML view of the child form, include this as a javascript function and call it on Unload of the child form or on button click.

window.opener.document.getElementById('txtParent').value = window.document.getElementById('txtChild').value

In the parent form you can open the child window by using window.open in the Response.Write method.
Check out my other post on the using the window.open parameters.