Question

Internet Explorer appears to be the only major browser that does not support pushState to handle history for AJAX submissions. So everywhere I have:

$.bbq.pushState(hash);

in my AJAX code, I have to add another line:

$.ajax(hash);

This of course causes a double-submission in all non-IE browsers that DO support submission via pushState().

What can I do to avoid these double submissions?

Answer 1

Just call $.ajax(hash); in a conditional statement only if the history.pushState is not natively supported

if (!history.pushState) {
   $.ajax(hash);
}

I also suggest to refactor your code using a unique wrapper function accepting an hash as parameter with the necessary logic, e.g.

var pushStateWrapper = function(hash) {

    if (!history.pushState) {
       $.ajax(hash);
    }
    else {
       $.bbq.pushState(hash);
    }
}