window.onbeforeunload handling ok and cancel options

问题

I have a window.onbeforeunload function which generates the default message "Are you sure you want to navigate away from this page...." . If we click on "OK" we are redirected to a new link and if we press "cancel" we are redirected back to the same page.

I want to save some data from the page when we press "ok" and move away from the page. How can we know if "ok" or "cancel" has been pressed , then make an event call and continue with the "ok"/"cancel" option.

回答1:

function leavePage() {
    //do your thing like saving the data in the session
    return "Some data entered may be lost."; //a text needs to be returned
}

window.onbeforeunload = leavePage;

回答2:

A possible approach might be to hook into the onunload event as well, and if that handler is called, you know that the user chose OK.

In onbeforeunload, set a timeout callback that is called some time afterwards (e.g. 1 second), and if it is called, the user might have selected Cancel.

Not sure how safe this is regarding race conditions though.

回答3:

Are you using JavaScript 'confirm' dialog?

if(confirm("Are you sure you want to navigate away from this page....")) {
    // OK was pressed
} else {
    // Cancel was pressed
}

来源：https://stackoverflow.com/questions/5579326/window-onbeforeunload-handling-ok-and-cancel-options