js将对象居中函数

//将对象居中显示function moveMiddle(obj){if(!obj) return ;obj.style.display = "block";var screenWidth = document.documentElement.clientWidth;var screenHeight = document.documentElement.clientHeight;var scrollPosY = 0;var scrollPosX = 0if(typeof window.pageYOffset != 'undefined'){scrollPosY = window.pageYOffset;}else if(typeof document.documentElement != 'undefined'){scrollPosY = document.documentElement.scrollTop;}if(typeof window.pageXOffset != 'undefined'){scrollPosX = window.pageXOffset;}else if(typeof document.documentElement != 'undefined'){scrollPosX = document.documentElement.scrollLeft ;}var divWidth = obj.offsetWidth;var divHeight = obj.offsetHeight;var divLeft = parseInt((screenWidth - divWidth) / 2);var divTop = parseInt((screenHeight - divHeight) / 2);divTop = divHeight > screenHeight ? 10 : divTop + scrollPosY;divLeft = divWidth > screenWidth ? 10 : divLeft + scrollPosX;obj.style.left = divLeft + "px";obj.style.top = divTop + "px";}