[javascript] Browser back button handling

I am trying to handle browser back button event but i could not find any solution.

I want to ask user if he clicks on browser back button using "confirm box" if he chooses ok i have to allow back button action else i have to stop back button action.

Can any one help me in implementing this.

You can also add hash when page is loading:

location.hash = "noBack";

Then just handle location hash change to add another hash:

$(window).on('hashchange', function() {
    location.hash = "noBack";
});

That makes hash always present and back button tries to remove hash at first. Hash is then added again by "hashchange" handler - so page would never actually can be changed to previous one.