How to check whether Submit Button is disabled in JQuery ?

 How to check whether Submit Button is disabled in JQuery ?
        if($('#submitButton').is(':disabled')){
        //Code to be executed
       }

How to Enable button in Jquery  ?
         $('#submitButton').attr("disabled", false);

How to Disable button in Jquery  ?
        $('#submitButton').attr("disabled", true);

How to change value of Submit button in Jquery  ?
        $('#submitButton').val('Please wait ... Processing');


 Code :

$('#submitButton').click(function() {
                    if($('#submitButton').is(':disabled'))
                     {
                        $('#submitButton').attr("disabled", false);
                        $('#submitButton').val('Submit');
                     }
                    else
                    {
                       $('#submitButton').attr("disabled", true);
                        $('#submitButton').val('Please wait ... Processing');
                     }