div自写弹出对话框的问题


//浏览器类型及版本检测
function getOs() 
{ 
   var OsObject = ""; 
   if(navigator.userAgent.indexOf("MSIE")>0) { 
        return "MSIE"; 
   } 
   if(isFirefox=navigator.userAgent.indexOf("Firefox")>0){ 
        return "Firefox"; 
   } 
   if(isSafari=navigator.userAgent.indexOf("Safari")>0) { 
        return "Safari"; 
   }  
   if(isCamino=navigator.userAgent.indexOf("Camino")>0){ 
        return "Camino"; 
   } 
   if(isMozilla=navigator.userAgent.indexOf("Gecko/")>0){ 
        return "Gecko"; 
   } 
   
} //参数列表：
//txt:显示文本
//time:显示时间
//url:按“确定”后跳转的地址
//script:按“确定”后执行的脚本
//isdrav:是否可拖动
window.alert = function(txt,time,url,script,isdrav)
{     
    var shield = document.createElement("DIV");
    shield.id = "AlertDiv";
    shield.style.position = "absolute";
    shield.style.left = "0px";
    shield.style.top = "0px";
    shield.style.width = "100%";
    var sheight;
    if(getOs()=="MSIE")
    {
       shield.style.height=window.screen.height+getScrollTop();
    }
    else
    {
        shield.style.height="100%";
    }
    shield.style.background = "#333333";
    shield.style.textAlign = "center";
    shield.style.zIndex = "100000";
    shield.style.filter = "alpha(opacity=70)";
    var alertFram = document.createElement("DIV");
    alertFram.id="alertFram";
    alertFram.style.position = "absolute";
    alertFram.style.right = "50%";
    alertFram.style.bottom = "50%";
    alertFram.style.marginRight = "-125px";
    alertFram.style.marginBottom = "-75px";    
    alertFram.style.width = "250px";
    alertFram.style.height = "auto";
    //alertFram.style.background = "#fff";
    alertFram.style.textAlign = "center";
    alertFram.style.lineHeight = "";
    alertFram.style.zIndex = "100002";
    //strHTML的几个css要自己去改写了，这里就不给了
    strHtml = "<ul class='Alertform'>\n";
    strHtml += "<li ";
    if(isdrav!=null && isdrav =="true")
    {
    strHtml +=" onmousedown=\"oMove(event);\" title=\"按住鼠标左键可进行拖动\"  style='cursor:move;'  ";
    }
    strHtml += " class='Alerttitle'>XXXXX友情提醒:</li>\n";
    strHtml += "<li class='AlertMessage'>"+txt+"</li>\n";
     strHtml += "<li class='AlertBtn'><input type='submit' value=' 确定 ' onclick=\"remove();\"></li>\n";
    strHtml += "</ul>\n";
    alertFram.innerHTML = strHtml; 
    
    document.body.appendChild(alertFram);
    document.body.appendChild(shield);
    var c = 70;
    this.doAlpha = function(){
        if (c++ > 70){clearInterval(ad);return 0;}
        shield.style.filter = "alpha(opacity="+c+");";
    }
this.remove=function(){    if(url!=null && url!="")
    {
       //判断在哪里刷新
      if(url.split('|').length>1)
      {
        top.location.href=url.split('|')[1];
      }
      else
      {
        location.href = url;
      }
    }
    if(script!=null && script!="")
    {
       script;
    }
    alertFram.innerHTML="";
shield.style.filter = "";
shield.style.display="none";
shield.id = "";
shield.style.position = "";
shield.style.left = "";
shield.style.top = "";
shield.style.width = "";
shield.style.height ="";
shield.style.background = "";
shield.style.textAlign = "";
shield.style.zIndex = "0";
shield.style.filter = "";
alertFram.id="";
alertFram.style.position = "";
alertFram.style.left = "";
alertFram.style.top = "";
alertFram.style.marginLeft = "";
alertFram.style.marginTop = "";
alertFram.style.width = "";
alertFram.style.height = "";
alertFram.style.background = "";
alertFram.style.textAlign = "";
alertFram.style.lineHeight = "";
alertFram.style.zIndex = "0";
alertFram.style.display="none";
if(setime!=null)
{
clearInterval(setime);
}

}
var ad = setInterval("doAlpha()",1);
    alertFram.focus();
    document.body.onselectstart = function(){return false;};
    if(time!=""&&time!=0&&time!=null)
    {
    var setime=  setInterval("remove()",time);
    }
   
}var ie=document.all; 
var nie=document.getElementById&&!document.all; 
var otop,oleft;
var obj;
var isdrag=false;    
function oMove(e){            obj = nie?e.target : event.srcElement; 
    var topElement = "HTML";      
     while (obj.tagName != topElement && obj.id != "alertFram") { 
     obj = nie ? obj.parentNode : obj.parentElement; 
     } 
     if (obj.id=="alertFram") { 
     isdrag = true; 
    
     otop = nie ? e.clientY- obj.offsetTop:event.y - obj.offsetTop;
 oleft = nie ? e.clientX- obj.offsetLeft:event.x - obj.offsetLeft;
 //设置捕获范围
      if(obj.setCapture){
          obj.setCapture();
      }else if(window.captureEvents){
          window.captureEvents(Event.MOUSEMOVE);
      }
   
 obj.onmousemove = moveMouse;
obj.onmouseup = function()
{
obj.onmousemove = null;
obj.style.filter = null;
 //取消捕获范围
           if(obj.releaseCapture){
              obj.releaseCapture();
           }else if(window.captureEvents){
              window.captureEvents(Event.MOUSEMOVE);
           }
          
          //清除事件
          obj.onmouseup=null;
}  return false; 
 }}
function moveMouse(e)
{
 if (isdrag) { 
 var top =  nie ?   e.clientY - otop :   event.clientY - otop;
 var left = nie ?  e.clientX - oleft :  event.clientX - oleft;
     top = top>0?top:0;
     left = left>0?left:0;
     
     //top = top>document.body.scrollHeight?document.body.scrollHeight:top;
     left = left>document.body.scrollWidth-2-parseInt(obj.style.width)?document.body.scrollWidth-2-parseInt(obj.style.width):left;
     
 obj.style.top  = top+"px"; 
     obj.style.left  =  left+"px"; 
   }
   return false;}
document.onmouseup=new Function("isdrag=false"); 
function getScrollTop() {    
    var scrollPos = 0;     
    if (typeof window.pageYOffset != 'undefined') {     
       scrollPos = window.pageYOffset;     
    }     
    else if (typeof window.document.compatMode != 'undefined' &&     
       window.document.compatMode != 'BackCompat') {     
       scrollPos = window.document.documentElement.scrollTop;     
    }     
    else if (typeof window.document.body != 'undefined') {     
       scrollPos = window.document.body.scrollTop;     
    }     
    return scrollPos;    
}