$().ready(function(){
    $("form").submit( function () {
         var buttons = $(this).find(":image, :submit");
         setTimeout(function () {
             buttons.attr("disabled", true);
             setTimeout(function () {
                 buttons.attr("disabled", false);
             }, 3000);
         }, 1);
    }).find(":image, :submit").attr("disabled", false);
});