can you create a server side textbox(asp.net) using javascript code.
how did yahoo create that textbox during the onclikc of a button (i.e while clicking add cc or add bcc).

In the most literal sense, Javascript cannot create a server side control because at the page has already been rendered and the viewstate has been set up. You could, however, have a javascript raise a server side method that could create the text box for you and re-render the page.

I do not use yahoo but, most likely, they may be using AJAX to unhide a DIV section of the form that allows you to enter CC and BCC names for an email. So that is also an option for you.

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