IOS输入框问题

 //  //ios输入框问题
function getScrollTop()
 {
     var scrollTop=0;
     if(document.documentElement&&document.documentElement.scrollTop)
     {
         scrollTop=document.documentElement.scrollTop;
     }
     else if(document.body)
     {
         scrollTop=document.body.scrollTop;
     }
     return scrollTop;
 }
 $('input').focus(function(){
     scrollHeight =  getScrollTop(); 
     console.log('此时页面的高度',scrollHeight)
 });
 $('input').blur(function(e){
     setTimeout(function(){
         window.scrollTo(0, scrollHeight)
     }, 200)
     console.log('失去焦点')
     e.preventDefault();
 });