function getElementLeft(element) { var actualLeft = element.offsetLeft; var current = element.offsetParent; while (current!==null) { actualLeft += current.offsetLeft; current = current.offsetParent; } return actualLeft; }

取得元素的左偏移量；

function getElementTop(element) { var actualTop = element.offsetTop; var current = element.offsetParent; while (current!==null) { <span> </span>actualTop += current.offsetTop; current = current.offsetParent; } return actualTop; }

取得元素的上偏移量；

利用offsetParent属性在Dom层次中逐级向上回溯，将每个层次偏移量合计。