var timeout_check_change_class;

function check_change_class( selector )
{
    $(selector).each(function(index, el) {
        var data_old_class = $(el).attr('data-old-class');
        if (typeof data_old_class !== typeof undefined && data_old_class !== false) 
        {

            if( data_old_class != $(el).attr('class') )
            {
                $(el).trigger('change_class');
            }
        }

        $(el).attr('data-old-class', $(el).attr('class') );

    });

    clearTimeout( timeout_check_change_class );
    timeout_check_change_class = setTimeout(check_change_class, 10, selector);
}
check_change_class( '.breakpoint' );


$('.breakpoint').on('change_class', function(event) {
    console.log('haschange');
});

使用最新的jquery突变

var $target = jQuery(".required-entry");
            var observer = new MutationObserver(function(mutations) {
                mutations.forEach(function(mutation) {
                    if (mutation.attributeName === "class") {
                        var attributeValue = jQuery(mutation.target).prop(mutation.attributeName);
                        if (attributeValue.indexOf("search-class") >= 0){
                            // do what you want
                        }
                    }
                });
            });
            observer.observe($target[0],  {
                attributes: true
            });

//任何代码更新div类required-entry是在$target 美元target.addClass(搜索类);

您可以绑定domsubtremodified事件。我在这里加一个例子:

HTML

<div id="mutable" style="width:50px;height:50px;">sjdfhksfh<div>
<div>
  <button id="changeClass">Change Class</button>
</div>

JavaScript

$(document).ready(function() {
  $('#changeClass').click(function() {
    $('#mutable').addClass("red");
  });

  $('#mutable').bind('DOMSubtreeModified', function(e) {
      alert('class changed');
  });
});

http://jsfiddle.net/hnCxK/13/

我建议您重写addClass函数。你可以这样做:

// Create a closure
(function(){
    // Your base, I'm in it!
    var originalAddClassMethod = jQuery.fn.addClass;

    jQuery.fn.addClass = function(){
        // Execute the original method.
        var result = originalAddClassMethod.apply( this, arguments );

        // call your function
        // this gets called everytime you use the addClass method
        myfunction();

        // return the original result
        return result;
    }
})();

// document ready function
$(function(){
    // do stuff
});

只是一个概念的证明:

查看要点，查看一些注释，并保持更新:

https://gist.github.com/yckart/c893d7db0f49b1ea4dfb

(function ($) {
  var methods = ['addClass', 'toggleClass', 'removeClass'];

  $.each(methods, function (index, method) {
    var originalMethod = $.fn[method];

    $.fn[method] = function () {
      var oldClass = this[0].className;
      var result = originalMethod.apply(this, arguments);
      var newClass = this[0].className;

      this.trigger(method, [oldClass, newClass]);

      return result;
    };
  });
}(window.jQuery || window.Zepto));

用法很简单，只要在你想观察和操作类的节点上添加一个新的监听器:

var $node = $('div')

// listen to class-manipulation
.on('addClass toggleClass removeClass', function (e, oldClass, newClass) {
  console.log('Changed from %s to %s due %s', oldClass, newClass, e.type);
})

// make some changes
.addClass('foo')
.removeClass('foo')
.toggleClass('foo');

依我看，更好的解决方案是结合@RamboNo5和@Jason的两个答案

我的意思是重写addClass函数并添加一个名为cssClassChanged的自定义事件

// Create a closure
(function(){
    // Your base, I'm in it!
    var originalAddClassMethod = jQuery.fn.addClass;

    jQuery.fn.addClass = function(){
        // Execute the original method.
        var result = originalAddClassMethod.apply( this, arguments );

        // trigger a custom event
        jQuery(this).trigger('cssClassChanged');

        // return the original result
        return result;
    }
})();

// document ready function
$(function(){
    $("#YourExampleElementID").bind('cssClassChanged', function(){ 
        //do stuff here
    });
});