<script>

///用户数据结构
function _tagUser()
{
 this.UserId = 0; //0-4
 this.UserName = ""; //5-

 this.Parse = function(VarTypeUser)
 {
  for (var i=0;i<VarTypeUser.length;i++)
   VarTypeUser[i] = String.fromCharCode(VarTypeUser.charCodeAt(i)^0xFFFF);
  this.UserId = VarTypeUser.substr(0,4); //0-4
  this.UserName = VarTypeUser.substr(5); //4--
 }
 this.ToString = function()
 {
  var str = this.UserId.toString();
  while (str.length<5)
  {
   str += "\u0000";
  }
  str += this.UserName;
  for (var i=0;i<str.length;i++)
  {
   str[i] = String.fromCharCode(str.charCodeAt(i)^0xFFFF);
  }
  return str;
 }
}

//结构体的应用
var User1 = new _tagUser();

User1.UserId = "54321";
User1.UserName = "zilin";

//假如这里通过了网络传输并想把数据解释到User2中，memcpy功能

var User2 = new _tagUser();
User2.Parse(User1.ToString());
alert("User2.UserId\t= "+User2.UserId +"\r\nUser2.UserName\t= "+User2.UserName);
</script>