"JavaScript" Seconds countdown timer

I. BASIC OBJECTIVES

Design a countdown timer in JavaScript, and once the time is done, the button becomes non-clickable.

Specific effects such as, in order to illustrate the problem, the tune to every 50 milliseconds, that is, every 0.05 jumps a table,

When really used, put window.onload=function () {...} In the SetInterval ("Clock.move ()", 50), and from 50 to 1000.

Before the time runs out, the button can still be clicked.

After the time runs out, the button cannot be clicked.

Second, the production process

<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "Http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">

"JavaScript" Seconds countdown timer