javascript仿百度输入框提示自动下拉补全

<code class="language-html">

 
 <title> New Document </title>
 <meta name="Generator" content="EditPlus">
 <meta name="Author" content="">
 <meta name="Keywords" content="">
 <meta name="Description" content="">
 <script type="text/javascript" src="/Public/js/jquery-1.7.1.min.js"></script>
  <script type="text/javascript">
  /*自动下拉补全 zhk */
  var highlightindex=-1;//当前高亮的节点
 $(document).ready(function(){
 var wordInput=$("#word");
 var wordInputOffset=wordInput.offset();
  
  $("#auto").hide().css("border","1px black solid").css("position","absolute")
  .css("top",wordInputOffset.top+wordInput.height()+5+"px")
  .css("left",wordInputOffset.left+"px").width(wordInput.width()+2);
  
 wordInput.keyup(function (event){
  
  var myEvent=event||window.event;
  var keyCode=myEvent.keyCode;
  if(keyCode>=65&&keyCode<=90||keyCode==8||keyCode==46){
  
   var wordText=$("#word").val();
   var autoNode=$("#auto");
   if(wordText!=""){
    
     
    var wordNodes=$("span");
     
    autoNode.html("");
    wordNodes.each(function(i){
     var wordNode=$(this);
     var newDivNode=$("<div>").attr("id",i);
       
     newDivNode.html(wordNode.text()).appendTo(autoNode);
     newDivNode.mouseover(function(){//鼠标进入
      if(highlightindex!=-1){
        $("#auto").children("div").eq(highlightindex)
        .css("background-color","white");
       }
       highlightindex=$(this).attr("id");
       $(this).css("background-color","red");
      })
  
      newDivNode.mouseout(function(){//鼠标移除
       $(this).css("background-color","white");
       
       })
newDivNode.click(function(){//点击
       var comText=$(this).text();
       $("#auto").hide();
     highlightindex=-1;
     $("#word").val(comText);
       })
  
    })
    if(wordNodes.length>0){
     autoNode.show();
    }else{
     autoNode.hide();
     highlightindex=-1;
     }
    
   }else{
   autoNode.hide();
    highlightindex=-1;
    }
  
   }else if(keyCode==38||keyCode==40){
     if(keyCode==38){//向上
      var autoNodes=$("#auto").children("div");
       if(highlightindex!=-1){
        autoNodes.eq(highlightindex).css("background-color","white");
         highlightindex--;
       }else{
        highlightindex=autoNodes.length-1;
       }
        
       if(highlightindex==-1){
        highlightindex=autoNodes.length-1;
       }
       autoNodes.eq(highlightindex).css("background-color","red");
     }
     if(keyCode==40){
      var autoNodes=$("#auto").children("div");
       if(highlightindex!=-1){
        autoNodes.eq(highlightindex).css("background-color","white");
       }
       highlightindex++;
       if(highlightindex==autoNodes.length){
        highlightindex=0;
       }
       autoNodes.eq(highlightindex).css("background-color","red");
     }
   }else if(keyCode==13){
      
    if(highlightindex!=-1){
     var comText=$("#auto").hide().children("div").eq(highlightindex).text();
     highlightindex=-1;
     $("#word").val(comText);
     }else{
      alert("文本框中的【"+$("#word").val()+"】被提交了");
      $("#auto").hide();
       $("#word").get(0).blur();//失去焦点
     }
    }
  });
  
  $("input [type='button']").click(function(){
   alert("文本框中的【"+$("#word").val()+"】被提交了");
  });
  
  
})
</script>
 
  
 
 <input type="text" id="word">
<input type="button" value="提交">
<div id="auto"></div>
<p>
<span>aaa</span>
<span>abc</span>
<span>abd</span>
<span>bbc</span>
<span>beb</span>
<span>cer</span>
<span>erd</span>
<span>beg</span>
</p>
<p>
 
</p></code>