How to display this message at exception?

$.ajax({

        type: "POST",

        url: 'url for ajax call',

        dataType: "text",

        success: function (data) {

          //do if you want to show some success message

        },

        error: function (XMLHttpRequest, textStatus, errorThrown) {

             { alert("error: " + textStatus + errorThrown); }

// or you can use colorbox(jquery) to show some bueatiful dailog boxes

        }

    });

In your application you can use try catch to throw the error to the ajax call, or you can customize your exception block to return it as a message.

In that case you need to modify your success block in Ajax call to check for error