JavaScript::Detect When Browser is Closed

Detect When Browser is Closed

function checkBrowser() {

  // triggers on clicking the close button, Alt+F4 , File->Close 

  if(window.event.clientX < 0 && window.event.clientY < 0) {

    window.open("somefile.htmllosewindow",'left=12000,top=1200,width=120,height=50');

  }

}