Javascript 知识点随笔

怎么设置块里面的内容块都水平垂直居中

    window.onload=function(){
            var obox=document.getElementById("box"); //外框块
            var oantzone=document.getElementById("antzone");　//目标块
            var w=oantzone.offsetWidth;
            var h=oantzone.offsetHeight;
            oantzone.style.position="absolute";
            oantzone.style.left="50%";
            oantzone.style.top="50%";

            oantzone.style.marginLeft=-(w/2)+"px";
            oantzone.style.marginTop=-(h/2)+"px";
        }