//根据某ID号获取该元素的页面位置
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    // safari & opera    
 {
  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]};
}

//测试
function pos1(ida,bar)
{
  var pos=getElementPos(ida);
  var obj=document.getElementById(ida); 
  var w=obj.offsetWidth; //菜单条的宽度
  var h=obj.offsetHeight;//菜单条高度

  //var x=event.clientX; //鼠标的x位置
  var tar=document.getElementById(bar); //下拉菜单

      tar.onmouseover=function(){this.style.display="block"};
      tar.onmouseout=function(){this.style.display="none"};
      obj.onmouseout=function(){tar.style.display="none"};
      tar.style.display="block";
   
    
      tar.style.top=pos.y+h-2;
      tar.style.left=pos.x+3;
     
}

function dirSec(type)
{
	num=1;
	if(type==0)
	{
		
		type=1;
	}
    var obj=document.getElementById("main_left").getElementsByTagName("a");
   // alert(type);
    var num=type-1;
    obj[num].style.color='red';
}