Ruby's Louvre

每天学习一点点算法

导航

javascript 绑定切换

jQuery有关事件绑定的函数太丰富了，今天由于某需求，需要一种每次点击触发不同的回调函数的效果，因此瞄一瞄jQuery的API，发现toggle正是我要的，于是也给我框架添一个。但jQuery的实现太复杂了，闭包套嵌过多，我换另一种思路轻松实现了它。

下面是jQuery的实现：

 
//===============代理函数===============
        proxy: function( fn, proxy, thisObject ) {
            if ( arguments.length === 2 ) {
                if ( typeof proxy === "string" ) {
                    thisObject = fn;
                    fn = thisObject[ proxy ];
                    proxy = undefined;

                } else if ( proxy && !jQuery.isFunction( proxy ) ) {
                    thisObject = proxy;
                    proxy = undefined;
                }
            }

            if ( !proxy && fn ) {
                proxy = function() {
                    return fn.apply( thisObject || this, arguments );
                };
            }

            // Set the guid of unique handler to the same of original handler, so it can be removed
            if ( fn ) {
                proxy.guid = fn.guid = fn.guid || proxy.guid || jQuery.guid++;
            }

            // So proxy can be declared as an argument
            return proxy;
        },
//===============绑定切换函数===============
      toggle: function( fn ) {
        // Save reference to arguments for access in closure
        var args = arguments, i = 1;

        // link all the functions, so any of them can unbind this click handler
        while ( i < args.length ) {
          jQuery.proxy( fn, args[ i++ ] );
        }

        return this.click( jQuery.proxy( fn, function( event ) {
          // Figure out which function to execute
          var lastToggle = ( jQuery.data( this, "lastToggle" + fn.guid ) || 0 ) % i;
          jQuery.data( this, "lastToggle" + fn.guid, lastToggle + 1 );

          // Make sure that clicks stop
          event.preventDefault();

          // and execute the function
          return args[ lastToggle ].apply( this, arguments ) || false;
        }));
      },

这是我的实现：

        toggle:function(/*fn1,fn2,fn3*/){
            var callback = function(event){
                var self = arguments.callee;
                try{
                    self["fn"+self._toggle].call(this,event)
                }catch(e){
                    self._toggle =0 ;
                    self["fn"+self._toggle].call(this,event)
                }
                self._toggle ++
            }
            for(var i=0;i<arguments.length;i++){
                callback["fn"+i] = arguments[i];
            }
            return this.click(callback)
        }

由于我不可能把我的事件模块放出来，它与jQuery的事件模块一样精致与复杂，换言之，一样易碎，强行分割就动弹不了。不过结合我早期放出的addEvent函数，还是能做出来的，虽然事件队列与事件对象还没有现整化。

      var addEvent = function(el, type, fn) {
        if (el.addEventListener) {
          el.addEventListener(type, fn, false);//DOM2.0
        }else if (el.attachEvent) {
          el.attachEvent('on' + type, function(){
            fn.call(el,window.event)
          });
        }
      }
      var toggle = function(el/*,fn1,fn2,fn3*/){
        var callback = function(event){
          var self = arguments.callee;
          try{
            self["fn"+self._toggle].call(this,event)
          }catch(e){
            self._toggle =0 ;
            self["fn"+self._toggle].call(this,event)
          }
          self._toggle ++
        }
        var fns = [].slice.call(arguments,1);
        for(var i=0;i<fns.length;i++){
          callback["fn"+i] = fns[i];
        }
        addEvent(el,"click",callback);
      }
//=========经群里高人指点，继续简化与优化=====
      var toggle2 = function(el) {
        var fns = [].slice.call(arguments, 1),
        backup = fns.concat();
        addEvent(el, 'click', function(e){
          if (!fns.length) { fns = backup.concat()}
          fns[0].call(this,e);
          fns.shift();
        });
      };

用法与例子：

posted on 2010-06-15 21:44  司徒正美  阅读(3710)  评论(9)  编辑  收藏  举报