Asp.Net get value from popup window in javascript

Question

I am using a user control and I need to call a popup, which asks a question, and I need to send the response (true or false) back to the user control that invokes the popup. I declared a hidden field to store the value in it from client-side so I can have access to it from the code behind and then execute further code. I have the following code: ASP.Net function confirmNoCallList() { debugger; var resp = confirm("¿Seguro/a que desea agregar a este subscriptor a la lista de 'No Llamar'?"); window.opener.document.getElementById('hfAddToNoCallList').value = resp; } . . . I am getting an error when the function hits the window.opener line. Any ideas on how to do this the right way? JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

You have to get the dynamic ClientID at runtime or pass it to a function and an arg that can then find it: document.getElementById('<%= hfAddToNoCallList.ClientID"%>').value = resp; or function confirmNoCallList(hiddenField) { debugger; var resp = confirm("¿Seguro/a que desea agregar a este subscriptor a la lista de 'No Llamar'?"); document.getElementById(hiddenField).value = resp; }