/*
* 动态显示下拉菜单
* 陈坚
*/
function Navigation(){
}
var xmlHttpRequest;
Navigation.displaySubMenu = function(li,tdmain,nav,submenu0,id,url)
{
   if (window.XMLHttpRequest){
      xmlHttpRequest=new XMLHttpRequest();
   }else if (window.ActiveXObject){
      xmlHttpRequest=new ActiveXObject("Microsoft.XMLHTTP");    
   }
 	//alert(url);
   //var url="commonIndex.credit?action=getSubmenuColumns&pid="+id;
   if(xmlHttpRequest)
   {
       xmlHttpRequest.open("GET",url,true);
       xmlHttpRequest.onreadystatechange=function(){
          Navigation.callback(li,tdmain,nav,submenu0);
       };
       xmlHttpRequest.send(null);
   }
   
};

Navigation.callback = function(li,tdmain,nav,submenu0){
    if(xmlHttpRequest.readyState == 4)
    {
        if(xmlHttpRequest.status == 200)
        {
           // Navigation.parseMessage();
           Navigation.clearPreviousResults(submenu0);
            Navigation.showSubMenu(li,tdmain,nav,submenu0);
            //document.getElementById("results").innerHTML=xmlHttpRequest.responseText;
            //alert("The server reply:"+xmlHttpRequest.responseText);
        }else{
            alert("Not able to retrieve description"+xmlHttpRequest.statusText);
        }
    }   
};
//清空下拉菜单
Navigation.clearPreviousResults = function (submenu0) {
            var ul = document.getElementById(submenu0);
            ul.innerHTML  = "";
            
};
//显示下拉菜单
Navigation.showSubMenu = function (li,tdmain,nav,submenu0) {        
            var resText = xmlHttpRequest.responseText;
            var json = JSON.parse(resText);
            var ul = document.getElementById(submenu0);
            for(var i = 0; i <json.columnsList.length; i++){
               var menuli = document.createElement("li");
               var lihref = document.createElement("a");
               lihref.href = json.columnsList[i].url;
               if(json.columnsList[i].name != "保单查询" && json.columnsList[i].name != "理赔查询")
                  lihref.target = "index_content";
               else
                  lihref.target = "_blank";
               var litext = document.createTextNode(json.columnsList[i].name);
             
               lihref.appendChild(litext); 
               menuli.appendChild(lihref);
               ul.appendChild(menuli);
            }
            //alert(ul.innerHTML);
            var subMenu = document.getElementById(li);
            var tdmain = document.getElementById(tdmain);
            var nav = nav;
           
            var divleft = subMenu.offsetLeft;
            var divwidth = subMenu.offsetWidth;
            var tdleft = tdmain.offsetLeft;
            var tdwidth = tdmain.offsetWidth;
            var navleft = nav.offsetLeft;
            var navwidth = nav.offsetWidth;
            
            divleft = tdleft+navleft+navwidth/2-divwidth/2;
            if(divleft<tdleft||(tdleft+navleft+navwidth/2-divwidth/2)<tdleft)
            {
              
               subMenu.style.left = tdleft+20;
               
             }else if((divleft+divwidth)>(tdleft+tdwidth))
             {
               
               subMenu.style.left = (tdleft+tdwidth)-divwidth-20;
             }
             else{
                        
                subMenu.style.left = tdleft+navleft+navwidth/2-divwidth/2;
             }
             subMenu.style.visibility = "visible";
            
};

Navigation.displaySubMenu1= function (li) {
            
           var subMenu = document.getElementById(li);             
            subMenu.style.visibility = "visible";
                         
};

Navigation.hideSubMenu = function (li) {
          var subMenu = document.getElementById(li);
          subMenu.style.visibility = "hidden";         
 };