if (window.location.search.substring(10) == "1")
{
   category = ("flash");
}
if (window.location.search.substring(10) == "2")
{
   category = ("javascript");
}
if (window.location.search.substring(10) == "3")
{
   category = ("css");
}

var loc = window.location.search.substring(10);
switch (loc) {
   case '1':
       ...
   case '2' :
       .........
   default :
       ............
}

var t={'1':"flash",'2':"javascript",'3':"css"};
category= (t[window.location.search.substring(10)]);

function T(){}       //我是类
T.prototype.1='flash';
T.prototype.2='javascript';
T.prototype.3='css';
var t = new T();

function T()        //我是类
{
    this.1 = 'flash';  
    //或者写成var 1 = 'flash'; ，this和var是在对象被调用的时候是有区别的，本文不解释此处
    this.2 = 'javascript';  
    this.3 = 'css';  
    this.Method = function(){alert("XXX");};//类有属性，当然可以有方法。
}
var t = new T();