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

 
  
  
  
   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;
   }