JS onbeforeunload Ajax使用 function send(){ $.ajax({ url: "url", async: true // 这里要用异步 }) } window.onbeforeunload(){ send() return true; } 注意:Ajax中一定要用异步 否则下面的异常 "NetworkError: Failed to execute 'send' on 'XMLHttpRequest': Failed to load '': Synchronous XHR in page dismissal. See https://www.chromestatus.com/feature/4664843055398912 for more details."