帮忙写一个JS，完成一个有趣的特效

Question

主要功能是一个横向的菜单如下：
<a> <b> <c> <d> <e>
点击<a>时它和它附近的二个都打开如下：
<    a    > <    b    > <     c    > <d> <e>
点击<d>时它和它附近的二个都打开其它关闭如下：
<a> <b> <     c    > <    d    > <    e    >请大家帮忙

Answer 1

大体思路  <div id="test">
       <span style="cursor:pointer;" lang="0">+a+</span>
       <span style="cursor:pointer;" lang="0">+b+</span>
       <span style="cursor:pointer;" lang="0">+c+</span>
       <span style="cursor:pointer;" lang="0">+d+</span>
       <span style="cursor:pointer;" lang="0">+e+</span>
   </div>   Node.prototype.prev = function(){
           var  pre = this.previousSibling;
           while(pre&&pre.nodeName.toLowerCase()==="#text"){
                  pre = pre.previousSibling;
           }
           return pre;
        }        Node.prototype.next = function(){
            var next = this.nextSibling;
            while(next&&next.nodeName.toLowerCase()==="#text"){
                next = next.nextSibling;
            }
            return next;
        }        window.onload = function(){
            var _prev,_nex,current;
            var spans = document.getElementById("test").getElementsByTagName("span");
            for(var i=0; i<spans.length; i++){
                spans[i].onclick = function(){
                   if(_prev){
                       _prev.innerHTML = _prev.innerHTML.replace(/-/g,"\+");
                       _prev.lang = "0";
                   }
                   if(_nex){
                       _nex.innerHTML = _nex.innerHTML.replace(/-/g,"\+");
                       _nex.lang = "0";
                   }
                   if(current){
                      current.innerHTML = current.innerHTML.replace(/-/g,"\+");
                       current.lang = "0";
                   }
                   var pre = this.prev();
                    var next = this.next();
                    if(pre){
                       _prev = pre;
                       if(pre.lang=="0"){
                           pre.innerHTML = pre.innerHTML.replace(/\+/g,"-");
                           pre.lang = "1";
                       }
                       else{
                            pre.innerHTML = pre.innerHTML.replace(/-/g,"\+");
                           pre.lang = "0";
                       }
                    }
                    if(next){
                        _nex = next;
                        if(next.lang=="0"){
                           next.innerHTML = next.innerHTML.replace(/\+/g,"-");
                           next.lang = "1";
                       }
                       else{
                            next.innerHTML = next.innerHTML.replace(/-/g,"\+");
                           next.lang = "0";
                       }
                    }
                     if(this.lang=="0"){
                           this.innerHTML = this.innerHTML.replace(/\+/g,"-");
                           this.lang = "1";
                       }
                       else{
                            this.innerHTML = this.innerHTML.replace(/-/g,"\+");
                           this.lang = "0";
                       }
                    current = this;
                }
            }
        }

Answer 2

以上代码不适合IE6，FF下测试