Check if changes saved before unload

Question

I have the following JavaScript

EDIT: included assignments for changesSaved

 var changesSaved = true;

    $(document).ready(function ()         


        

Answer 1

function bye(){
    if(changesSaved) {
        return "You havent saved your changes."
    }
}

This is how I do it.

or in pure JavaScript:

window.onbeforeunload = function() {
    if (changesSaved) {
        return "You haven't saved your changes.";
    }
};