jquery ajax with async false hangs firefox

Question

I have a code that calls $.ajax like this :

$.ajax({

                        type: "POST",
                        url: "/sandbox/graphloader/mock3",
                        async: false,
                        data: {calInput1:dates[0], calInput2:dates[1]},
                        success: function(data){
                            data=eval(data);
                            for(var x in data[0]){
                                //alert(data[0][x]);
                                //fill columns here;
                            }

                            fillPercents(column);
                        }});

now, this works in all browsers, other than Firefox. firebug shows it is getting reply back from post, but for some unknown error, it is not displaying the data. What might be the problem ?

Answer 1

This behavior is by design.

Never use async: false.
Since Javascript runs on the UI thread, an async: false request will freeze the browser until the server replies.