input 唤起键盘后遮住页面元素

var windheight = $(window).height();  /*未唤起键盘时当前窗口高度*/
        
$(window).resize(function(){
   var docheight = $(window).height();  /*唤起键盘时当前窗口高度*/        
   if(docheight < windheight){            /*当唤起键盘高度小于未唤起键盘高度时执行*/
      $(".submit").css("position","static");
   }else{
      $(".submit").css("position","fixed");
   }           
});