原生js的触焦onfcus和失焦onblur

var inp1=document.getElementById('inp1');
     inp1.onfocus=function(){
       if(inp1.value=="请输入..."){
         inp1.value="";
         inp1.style.color="white";
       }
     } 

   inp1.onblur=function(){
       if(inp1.value==""){
         inp1.value="请输入...";
         inp1.style.color="#ccc";
       }
   }