jQuery Form Plugin – jquery.form.js

function  sendSuccess(data, status)  {
    if(status!=='success') {
        alert('Error');
        return false;
    }

    alert(data.message);
}

$('#myForm2').ajaxSubmit({
    dataType:'json',
    success: sendSuccess
});

// prepare the form when the DOM is ready
$(document).ready(function() {
    var options = {
        target:        '#output2',   // target element(s) to be updated with server response
        beforeSubmit:  showRequest,  // pre-submit callback
        success:       showResponse  // post-submit callback

        // other available options:
        //url:       url         // override for form's 'action' attribute
        //type:      type        // 'get' or 'post', override for form's 'method' attribute
        //dataType:  null        // 'xml', 'script', or 'json' (expected server response type)
        //clearForm: true        // clear all form fields after successful submit
        //resetForm: true        // reset the form after successful submit

        // $.ajax options can be used here too, for example:
        //timeout:   3000
    };

    // bind to the form's submit event
    $('#myForm2').submit(function() {
        // inside event callbacks 'this' is the DOM element so we first
        // wrap it in a jQuery object and then invoke ajaxSubmit
        $(this).ajaxSubmit(options);

        // !!! Important !!!
        // always return false to prevent standard browser submit and page navigation
        return false;
    });
});

// pre-submit callback
function showRequest(formData, jqForm, options) {
    // formData is an array; here we use $.param to convert it to a string to display it
    // but the form plugin does this for you automatically when it submits the data
    var queryString = $.param(formData);

    // jqForm is a jQuery object encapsulating the form element. To access the
    // DOM element for the form do this:
    // var formElement = jqForm[0];

    alert('About to submit: \n\n' + queryString);

    // here we could return false to prevent the form from being submitted;
    // returning anything other than false will allow the form submit to continue
    return true;
}

// post-submit callback
function showResponse(responseText, statusText, xhr, $form)  {
    // for normal html responses, the first argument to the success callback
    // is the XMLHttpRequest object's responseText property

    // if the ajaxSubmit method was passed an Options Object with the dataType
    // property set to 'xml' then the first argument to the success callback
    // is the XMLHttpRequest object's responseXML property

    // if the ajaxSubmit method was passed an Options Object with the dataType
    // property set to 'json' then the first argument to the success callback
    // is the json data object returned by the server

    alert('status: ' + statusText + '\n\nresponseText: \n' + responseText +
        '\n\nThe output div should have already been updated with the responseText.');
}