Question

I have two pages

1. Master page
2. page using the master page

I am opening a pop up using “window.open” in the second page.
I have textbox control in the second page and trying the find the control in the pop up page using below code.

window.opener.document.getElementById('textbox').value

This code could not found out the control.

Then I checked the page source of second form and dound out the format of control id. It was like below.

“_ctl0_ContentPlaceHolder1_textbox”

and changed the code to below and got success.
“window.opener.document.getElementById(‘_ctl0_ContentPlaceHolder1_textbox’).value”

My query is -> I am not about this approach. Please correct if i am doing anything wrong.

Answer 1

With ASP.NET 4.0 you have the option to set ClientIDMode that could help you in this case.
Setting ClientIDMode to “Static” will ensure that your ID value will not be altered by the framework.

In your page where you have textbox:

<asp:TextBox ID="MyTextBox" runat="server" ClientIDMode="Static" /> 

Then you should be able to get the value by doing something like this:

window.opener.document.getElementById('textbox').value

Ref: MSDN – ClientIDMode