兼容firefox的offsetX,计算鼠标位置（触发元素与窗口的距离,计算从触发到root间所有元素的offsetLeft值之和 [code] <script type='text/javascript'> var $id=function(id){ return document.getElementById(id) || id; } function sizer(e){ var e=window.event || e, posX=(e.offsetX==undefined) ? getOffset(e).offsetX : e.offsetX ; $id('ct').innerHTML='offsetX(包括FF):'+posX +'
clientX:' +e.clientX +'
layerX:' +e.layerX +'
pageX:'+ e.pageX ; } function getOffset(e) { var target = e.target; if (target.offsetLeft == undefined) { target = target.parentNode; } var pageCoord = getPageCoord(target); var eventCoord = { x: window.pageXOffset + e.clientX, y: window.pageYOffset + e.clientY }; var offset = { offsetX: eventCoord.x - pageCoord.x, offsetY: eventCoord.y - pageCoord.y }; return offset; } function getPageCoord(element) { var coord = {x: 0, y: 0}; while (element) { coord.x += element.offsetLeft; coord.y += element.offsetTop; element = element.offsetParent; } return coord; } </script> [/code]