Question

I’m starting to see a pattern that I’m using for all my $.ajax calls, so I’d like to write a jQuery plugin called myAjax:

var myXHR = $.myAjax(myURL, mySettings)

and it will will always include the following:

myXHR.done(function(result) {
    if (result.MSG) {
        $('#msg').html(result.MSG).addClass('alert alert-info');
    }
})
.fail(function(A,B,C) {
    $('#msg').html(C).addClass('alert alert-info');
});

I also want to include the defaults that I use regularly:

var ajaxDefaults = {};
ajaxDefaults.type= 'POST'
ajaxDefaults.dataType='json';
$.ajaxSetup(ajaxDefaults);

Q: How do I write a plugin to do those two things:

1. Include the defaults for type and dataType
2. Include a default .done and .fail

Answer 1

To set a plugin in jQuery is quite simple as you follow your own documentation.

JQuery documentation

So for your case it will:

(function($) {
      $.extend($.fn, {
    myAjax: function(url, options) {
        var opts = $.extend({}, $.fn.ajaxDefaults, options);
        //your code....
            }
    /*
    * plugn defaults
    */
    ajaxDefaults : {
        type: "POST",
        dataType: "json"
    }
    }); 
}(jQuery)); 

I hope this help.