碰撞封装

function pz(obj1,obj2){

      var L1 = obj1.offsetLeft;

      var R1 = obj1.offsetLeft + obj1.offsetWidth;

      var B1 = obj1.offsetTop + obj1.offsetHeight;

      var T1 = obj1.offsetTop;

      

      var L2 = obj2.offsetLeft;

      var R2 = obj2.offsetLeft + obj2.offsetWidth;

      var B2 = obj2.offsetTop + obj2.offsetHeight;

      var T2 = obj2.offsetTop;

      

      碰上返回true  碰不上返回false

      if( R2<L1 || R1<L2 || B1<T2 || B2<T1 ){ 

            return false;   // 碰不上条件

      }else{

            return true;   //碰上了

      }

}