var $getMouseX=function () {
  var evt=window.event;
  if (evt.pageX)
  {
	 return evt.pageX;
  }
  else if (evt.clientX)
  {
  	 var scrollLeft=0;
  	 if(document.documentElement.scrollLeft)
  	 {
  	 	scrollLeft=document.documentElement.scrollLeft;
  	 }
  	 else
  	 {
  	 	scrollLeft=document.body.scrollLeft;
  	 }
  	 
   	 return evt.clientX + scrollLeft;
  }  
  else
  { 
	return null;
  }
}
var $getMouseY=function () {
  var evt=window.event;
  if (evt.pageY)
  { 
	return evt.pageY;
  }
  else if (evt.clientY)
  {
  	var scrollTop=0;
  	if(document.documentElement.scrollTop)
  	{
  		scrollTop=document.documentElement.scrollTop;
  	}
  	else 
  	{
  		scrollTop=document.body.scrollTop;
  	}
    return evt.clientY + scrollTop;
  }
  else
  {
  	 return null;
  }
}

//通过name 和tagName获取相应的元素
var $getElementsByName=function(tagName,name){
	var targetElements=new Array();
	var allTagElements=document.getElementsByTagName(tagName);

	if(!(name&&name!=""))return targetElements;
	if(!(allTagElements&&allTagElements.length>0))return targetElements;
	
	
	for(var i=0;i<allTagElements.length;i++)
	{
		if(allTagElements[i].getAttribute("name")==name)
		{
			targetElements[targetElements.length]=allTagElements[i];
		}
	}	
	return targetElements;
}

var showInfo=function(id,lSchoolId)
{
   window.location.href="/announcement/show.htm?id="+id+"&lSchoolId="+lSchoolId;
}

var showTxt=function(showIndex)
{
	var titleDivs=$getElementsByName("DIV","switch_div");
	var title_imgDivs=$getElementsByName("DIV","switch_img");
	var title_textDivs=$getElementsByName("DIV","switch_text");
	var title_lis=$getElementsByName("LI","bgli")
	
	showTextInfo(showIndex,titleDivs,title_imgDivs,title_textDivs,title_lis);
	
}

//主题层的范围
var $getTargetArea=function(obj)
{
	if(!(obj&&obj!=null))return;
	
	var w1,w2,y1,y2=0;
	w1=getAbsLeft(obj)-180;
 
	w2=887;
	y1=getAbsTop(obj);
	y2=y1+183;
	
	var area=new Array();
	area[0]=w1;
	area[1]=w2;
	area[2]=y1;
	area[3]=y2;
	
	return	area;
}

//如果鼠标不在主题层范围内 触发enter事件
$onmouseenter=function(obj)
{
	var areaArray=$getTargetArea(obj);
	if($getMouseX()>=areaArray[0]&&$getMouseY()>=areaArray[2]
		&&$getMouseX()<=areaArray[1]&&$getMouseY()<=areaArray[3])
	{
		
		return true;
	}
	return false;
	
}



//改变图片
var showIndex=0;
var timerTitle=null;
var changeTitle=function()
{
	var titleDivs=$getElementsByName("DIV","switch_div");
	var title_imgDivs=$getElementsByName("DIV","switch_img");
	var title_textDivs=$getElementsByName("DIV","switch_text");
	var title_lis=$getElementsByName("LI","bgli")
	
	if(!(titleDivs&&titleDivs!=null))
	{
		return;
	}
	if(titleDivs.length==0)
	{
		return;
	}
	
	if(showIndex==titleDivs.length-1)
	{
		showIndex=0;
	}
	else
	{
		showIndex++;
	}
	
	showTextInfo(showIndex,titleDivs,title_imgDivs,title_textDivs,title_lis);
	
	startTimerTitle();
}

var showTextInfo=function(tmpIndex,titleDivs,title_imgDivs,title_textDivs,title_lis)
{
	if(!(titleDivs&&title_imgDivs&&title_textDivs&&title_lis))
	{
		return;
	}
	for(var i=0;i<titleDivs.length;i++)
	{
		var showOrHidden="none";
		var className="";
		if(i==tmpIndex)
		{
			showOrHidden="block";
			className="bgno";
		}
		titleDivs[i].style.display=showOrHidden;
		title_imgDivs[i].style.display=showOrHidden;
		title_textDivs[i].style.display=showOrHidden;
		
		if(!title_lis[i])
		{
			continue;
		}
		title_lis[i].setAttribute("class",className);
		title_lis[i].setAttribute("className",className);
		
		
	}
}

//清空计时器
var clearTimerTitle=function()
{
	if(timerTitle&&timerTitle!=null)
	{
		clearTimeout(timerTitle);
		timerTitle=null;
	}
}

var startTimerTitle=function()
{
	timerTitle=setTimeout("changeTitle()",10000);
}

window.onload=function(){
	
	showIndex=-1;
	changeTitle();
	document.body.onmousemove=function(){
		//获取当前显示的主题层
		var currTitle=null;
		var titleDivs=$getElementsByName("DIV","switch_div");
		//如果层信息不存在返回
		if(!(titleDivs&&titleDivs!=null))return;
		if(titleDivs.length==0)return;
		for(var i=0;i<titleDivs.length;i++)
		{	
			if(titleDivs[i].style.display=="block"||titleDivs[i].style.display=="")
			{
				currTitle=titleDivs[i];
				break;
			}
		}
		//判断鼠标是否在主题层的范围内
		var enterFlag=$onmouseenter(currTitle);
		
		if(enterFlag)
		{
			clearTimerTitle();
		}
		else
		{	
			if(timerTitle==null)
			{
				startTimerTitle();
			}
		}
		
	}
	
}

var getAbsLeft=function(obj){
	if(obj.offsetParent==null)
		return obj.offsetLeft;
	else{
		var leftParent=getAbsLeft(obj.offsetParent);
		return obj.offsetLeft+leftParent
	}
}
var getAbsTop=function(obj){
	if(obj.offsetParent==null)
		return obj.offsetTop;
	else{
		var topParent=getAbsTop(obj.offsetParent);
		return obj.offsetTop+topParent
	}
}