function GetCookieVal(offset) 
//获得Cookie解码后的值 
{ 
var endstr = document.cookie.indexOf (";", offset); 
if (endstr == -1) 
endstr = document.cookie.length; 
sReturn =  unescape(document.cookie.substring(offset, endstr)); 
iEnd  = sReturn.indexOf("=");
	if (iEnd != -1){
	   return sReturn.substring(0,iEnd);
	}else{
       return sReturn;
    }
} 
function SetCookie(name, value) 
//设定Cookie值 
{ 
var expdate = new Date(); 
var argv = SetCookie.arguments; 
var argc = SetCookie.arguments.length; 
var expires = (argc > 2) ? argv[2] : null; 
var path =  "/"; 
var domain = "17try.cn"; 
var secure = (argc > 5) ? argv[5] : false; 
//if(expires!=null) expdate.setTime(expdate.getTime() + ( expires * 1000 )); 
document.cookie = name + "=" + escape (value.replace(/\=/g,"$")) +((expires == null) ? "" : ("; expires="+ expdate.toGMTString()))+((path == null) ? "" : ("; path=" + path)) +((domain == null) ? "" : ("; domain=" + domain))+((secure == true) ? "; secure" : "");
} 
function DelCookie(name) 
//删除Cookie 
{ 
var exp = new Date(); 
exp.setTime (exp.getTime() - 1); 
var cval = GetCookie (name); 
document.cookie = name + "=" + cval + "; expires="+ exp.toGMTString(); 
} 
function GetCookie(name) 
//获得Cookie的原始值 
{ 
var arg = name + "="; 
var alen = arg.length; 
var clen = document.cookie.length; 
var i = 0; 
while (i < clen) 
{ 
var j = i + alen; 
if (document.cookie.substring(i, j) == arg) 
return GetCookieVal(j).replace(/\$/g,"="); 
i = document.cookie.indexOf(" ", i) + 1; 
if (i == 0) break; 
} 
return ""; 
} 


//17获取参数
function getArrtibute(str){
    totalStr = parent.document.URL;
	iStart   = 0;
	iEnd     = 0;
	isTrue   = true
	iValue   = "";
    iStart = totalStr.indexOf(str+"=")
	if (iStart == -1){
	  isTrue = false;
	}
	iStart = str.length + iStart + 1  //+1是去除等号
    iEnd = totalStr.indexOf("&",iStart)
	if(iEnd == -1){
	  iEnd = totalStr.length;
	}
    iValue =  totalStr.substring(iStart,iEnd);
	if((isTrue == true) && (iValue != "")){
	   SetCookie(str,iValue);
	   return iValue;
	}else{
       if(GetCookie(str) == "null" || GetCookie(str) == null){
          return "";
	   }else{
          return GetCookie(str);
	   }
	}
}

//设置from
getArrtibute("from");