JavaScript capture window closing event_javascript tips

1. Use javascript to redefine the window.onbeforeunload() event
Just define a function in javascript
function window.onbeforeunload() { alert("Close the window")}
The alert() event will be executed before closing the window. You can also let the user decide whether to close the window
function window.onbeforeunload() {
if (event.clientX>document.body.clientWidth && event.clientYwindow.event.returnValue="Are you sure you want to exit this page?";
}
2. Use the onUnload method
in the body tag Add the onUnload event
body onUnload="myClose()"
Then define the myClose() method in javascript
But the onUnload method is executed after closing the window, not before closing the window. If you want to To make a judgment before closing the window, please use the first method