javascript switch语句 。工作原理：switch 后面的 (n) 可以是表达式，也可以（并通常）是变量。然后表达式中的值会与 case 中的数字作比较，如果与某个 case 相匹配，那么其后的代码就会被执行。break 的作用是防止代码自动执行到下一行。

实例：

<script type=”text/javascript”>

//You will receive a different greeting based

//on what day it is. Note that Sunday=0,

//Monday=1, Tuesday=2, etc.

 

var d=new Date()

theDay=d.getDay()

 

switch (theDay)

   {

   case 5:

     document.write(“Finally Friday”)

     break

   case 6:

     document.write(“Super Saturday”)

     break

   case 0:

     document.write(“Sleepy Sunday”)

     break

   default:

     document.write(“I’m looking forward to this weekend!”)

}

</script>