JavaScript组件开发之输入框加候选框

1.兼容ie8 主要是事件兼容

var EventUtil = {
   on:function(elem,type,handler){
    if(elem.addEventListener){
     elem.addEventListener(type,handler,false);
    }else if(elem.attachEvent){
     elem.attachEvent("on"+type,handler);
    }
   },
   getEvent:function(event){
    return event||window.event;
   },
   getTarget:function(event){
    return event.target||event.srcElement;
   },
   getCharCode:function(event){
    if(typeof event.handler == "number"){
     return event.charCode;
    }else{
     return event.keyCode;
    }
   }
  }

2.对于候选框里面的内容使用事件代理，以及点击空白处消失

EventUtil.on(document.body,'click',function(e){
   stopPropagation(e);
   if(EventUtil.getTarget(e).nodeName=='BODY'){
    datalist.style.visibility = 'hidden';
    datalist.innerHTML ='';
   }
   if(EventUtil.getTarget(e).nodeName == "LI"){
    input.value = EventUtil.getTarget(e).innerHTML;
    datalist.style.visibility = 'hidden';
    datalist.innerHTML ='';
   }
  })

3.兼容模式下的防止冒泡

 function stopPropagation(e){
   e = window.event||e;
   if(document.all){
    e.cancelBubble = true;
   }else{
    e.stopPropagation();
   }
  }

4.效果图

5.完整代码

<!DOCTYPE html>
<html>
 <head>
  <meta charset="utf-8">
  <title></title>
  <style media="screen">
   html,body{margin: 0;padding: 0;height: 100%;width: 100%;}
   input{
    width: 200px;
    border:1px solid grey;
    padding: 0 2px;
    line-height: 1.5rem;
    box-sizing: border-box;
    outline: none;
   }
   ul{
    margin:0;
    width: 200px;
    padding: 0;
    list-style: none;
    box-sizing: border-box;
    padding: 1px;
    border:1px solid;
    border-color: grey;
    visibility: hidden;
   }
   li{
    line-height: 1.5rem;
    padding: 0 0 0 1px;
   }
   li:hover{
    background-color: grey;
   }
   .section{
    top:30%;
    left:50%;
    position: absolute;
    margin-left: -100px;
   }
  </style>
 </head>
 <body>
 <div class="section">
   <input id="search"/>
   <ul id="datalist">
   </ul>
 </div>
 </body>
 <script type="text/javascript">
  var EventUtil = {
   on:function(elem,type,handler){
    if(elem.addEventListener){
     elem.addEventListener(type,handler,false);
    }else if(elem.attachEvent){
     elem.attachEvent("on"+type,handler);
    }
   },
   getEvent:function(event){
    return event||window.event;
   },
   getTarget:function(event){
    return event.target||event.srcElement;
   },
   getCharCode:function(event){
    if(typeof event.handler == "number"){
     return event.charCode;
    }else{
     return event.keyCode;
    }
   }
  }
  function stopPropagation(e){
   e = window.event||e;
   if(document.all){
    e.cancelBubble = true;
   }else{
    e.stopPropagation();
   }
  }
  var input = document.getElementById('search');
  var datalist = document.getElementById('datalist');
  var list_array = ['aa','aab','abc'];
  function generatelist(array){
   var _innerHTML = '';
   for (var i = 0; i < array.length; i++) {
    _innerHTML += '<li>'+array[i]+'</li>';
   }
   datalist.innerHTML = _innerHTML;
  }
  function findInArray(s){
   var filter_array = [];
   if(s!=''){
    for (var i = 0; i < list_array.length; i++) {
     if(list_array[i].indexOf(s)===0){
      filter_array.push(list_array[i])
     }
    }
   }
   return filter_array;
  }
  input.onkeyup = function(){
   var new_array = findInArray(this.value);
   generatelist(new_array);
   if(new_array.length>0){
    setTimeout(function(){datalist.style.visibility = 'visible';},0);
   }else{
    setTimeout(function(){datalist.style.visibility = 'hidden';},0);
   }
  }
  EventUtil.on(document.body,'click',function(e){
   stopPropagation(e);
   if(EventUtil.getTarget(e).nodeName=='BODY'){
    datalist.style.visibility = 'hidden';
    datalist.innerHTML ='';
   }
   if(EventUtil.getTarget(e).nodeName == "LI"){
    input.value = EventUtil.getTarget(e).innerHTML;
    datalist.style.visibility = 'hidden';
    datalist.innerHTML ='';
   }
  })
 </script>
</html>