function getElementPos(elementId) {
 var ua = navigator.userAgent.toLowerCase();
 var isOpera = (ua.indexOf('opera') != -1);
 var isIE = (ua.indexOf('msie') != -1 && !isOpera); // not opera spoof
 var el = document.getElementById(elementId);
 if(el.parentNode === null || el.style.display == 'none') {

  return false;

 }      

 var parent = null;

 var pos = [];     

 var box;     

 if(el.getBoundingClientRect)    //IE

 {         

  box = el.getBoundingClientRect();

  var scrollTop = Math.max(document.documentElement.scrollTop, document.body.scrollTop);

  var scrollLeft = Math.max(document.documentElement.scrollLeft, document.body.scrollLeft);

  return {x:box.left + scrollLeft, y:box.top + scrollTop};

 }else if(document.getBoxObjectFor)    // gecko    

 {

  box = document.getBoxObjectFor(el); 

  var borderLeft = (el.style.borderLeftWidth)?parseInt(el.style.borderLeftWidth):0; 

  var borderTop = (el.style.borderTopWidth)?parseInt(el.style.borderTopWidth):0; 

  pos = [box.x - borderLeft, box.y - borderTop];

 } else 

 {

  pos = [el.offsetLeft, el.offsetTop];  

  parent = el.offsetParent;     

  if (parent != el) { 

   while (parent) {  

    pos[0] += parent.offsetLeft; 

    pos[1] += parent.offsetTop; 

    parent = parent.offsetParent;

   }  

  }   

  if (ua.indexOf('opera') != -1 || ( ua.indexOf('safari') != -1 && el.style.position == 'absolute' )) { 

   pos[0] -= document.body.offsetLeft;

   pos[1] -= document.body.offsetTop;         

  }    

 }              

 if (el.parentNode) { 

    parent = el.parentNode;

   } else {

    parent = null;

   }

 while (parent && parent.tagName != 'BODY' && parent.tagName != 'HTML') { // account for any scrolled ancestors

  pos[0] -= parent.scrollLeft;

  pos[1] -= parent.scrollTop;

  if (parent.parentNode) {

   parent = parent.parentNode;

  } else {

   parent = null;

  }

 }

 return {x:pos[0], y:pos[1]};

}


function a() {
	var pos=getElementPos("divId");

	alert("距左边距离"+ pos.x +",距上边距离"+pos.y);
}