網上一段JS，考來的，自定義監聽：

    $.event.special.valuechange = {

    		  teardown: function (namespaces) {
    		    $(this).unbind('.valuechange');
    		  },

    		  handler: function (e) {
    		    $.event.special.valuechange.triggerChanged($(this));
    		  },

    		  add: function (obj) {
    		    $(this).on('keyup.valuechange cut.valuechange paste.valuechange input.valuechange', 
    		    		obj.selector, $.event.special.valuechange.handler)
    		  },

    		  triggerChanged: function (element) {
    		    var current = element[0].contentEditable === 'true' ? element.html() : element.val()
    		      , previous = typeof element.data('previous') === 'undefined' ? element[0].defaultValue : element.data('previous')
    		    if (current !== previous) {	
    		      element.trigger('valuechange', [element.data('previous')])
    		      element.data('previous', current)
    		    }
    		  }
    		}
 

$(".class").on("valuechange",function(){
        	your function
        });