Dont ask confirm if user submit the form

Question

I am using following JavaScript code to warn a user if he tries to redirect to another page without submitting the form.

window.onbeforeunload = function() {         


        

Answer 1

maintain a state variable. when user click submit button set state to userSubmitted=True;
state variable may include a global variable or hidden control.

var userSubmitted=false;

$('form').submit(function() {
userSubmitted = true;
});

then check like this

window.onbeforeunload = function() {
    if(!userSubmitted)
        return 'Are you sure that you want to leave this page?';
};

PS : cross check for onbeforunload compatibility for cross browser.