[JavaScript] Countdown timer, javascript countdown timer

[JavaScript] Countdown timer, javascript countdown timer

I. Basic Objectives

Design a minute-second countdown timer in JavaScript. Once the time is complete, the button becomes unclickable.

The specific effect is shown in. To illustrate the problem, it is adjusted to 50 milliseconds, that is, the table jumps every 0.05,

In actual use, set setInterval ("clock. move ()", 50) in window. onload = function () {...} to 1000.

Before the time is used up, you can click the button.

After the time is used up, the button cannot be clicked.

Ii. Production Process

<! DOCTYPE html PUBLIC "-// W3C // dtd xhtml 1.0 Transitional // EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">