The Observer pattern for JavaScript---design patterns

Concept

The observer pattern, also called the Publish subscription pattern (Publish/subscribe), defines a one-to-many relationship that allows multiple observer objects to listen to a Subject object at the same time, notifying all observer objects when the state of the subject changes, so that they can automatically update themselves.

Role

1. Supports simple broadcast communication and automatically notifies all subscribed objects
2. After page loading the target object is very easy to have a dynamic association with the observer, adding flexibility
3. The abstract coupling relationship between the target object and the observer can be extended independently and reused

Precautions

Listen to the trigger before triggering

<script type= "Text/javascript" >    (function () {        varo = $({}); $.jianting=function() {o.on.apply (o, arguments); } $.fabu=function() {o.trigger.apply (o, arguments); } $.qingchu=function() {o.off.apply (o,arguments);    }    })(); $.jianting ('/test/ls ',function(e,a,b,c) {alert (a+"||" +b+ "| |" +c+ "| |");    }); $.jianting ('/test/ls ',function(e,a,b,c) {alert (' OK ');    }); SetTimeout (function() {$.fabu ('/test/ls ', [a]); }, 1000);</script>

The Observer pattern for JavaScript---design patterns