1     <script type="text/javascript">
 2     
 3         function add(num1,num2)
 4         { return num1+num2+200;}
 5         var sum=add(122,10000);
 6         window.document.write(sum);
 7         
 8     </script>
 9     <script type="text/javascript">
10         var add=new Function("num"," return num+200");　　　　//此时Function 这种方法用的比较少
11         var sum=add(122);
12         window.document.write(sum);
13         
14     </script>
15      
16 
17     <script type="text/javascript">
18     
19         var add=function(num1,num2){ return num1+num2+200;}
20         var sum=add(122,300);
21         window.document.write(sum);
22     </script>