How to sent some data from child window to parent window in ASP.NET

Question

hi this is kavita,
currently I m creating child window(c#,asp.net) but the problem is I want to sent some data from child window to parent window on closing child window. I use session but I have to refresh the page .I don't wnat it, i also use html n I have done it but data is coming only in html textbox not web textbox, Is there any other way without refresing the page and not html control.any sever side coding?