//obj1为运动的,Obj2为被撞的
function hitFun(obj1,obj2){
var l1=obj1.offsetLeft;
var t1=obj1.offsetTop;
var r1=l1+obj1.offsetWidth;
var b1=t1+obj1.offsetHeight;

var l2=obj2.offsetLeft;
var t2=obj2.offsetTop;
var r2=l2+obj2.offsetWidth;
var b2=t2+obj2.offsetHeight;
if (l1>r2||t1>b2||r1<l2||b1<t2) {
return false;
}
return true;
}

碰撞检测