JavaScript for closing the pop up window on both firefox ane iexplore

function closewindow()
{
window.open('','_self','');window.close();
return true;
}
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/*How to Call A JavaScript function through code behind */

ClientScript.RegisterStartupScript(GetType(), "", "");

//Like this
ClientScript.RegisterStartupScript(GetType(), "", "")

/*How to call a JavaScript function through code behind when page have update panel */

ScriptManager.RegisterStartupScript(Page, Page.GetType(), Guid.NewGuid().ToString(), "ShowSucessmsg();", true);