<!DOCTYPE html>
<html lang =“en”>
<HEAD>
<meta charset =“UTF-8”>
<meta name =“viewport”content =“width = device-width,initial-scale = 1.0”>
<meta http-equiv =“X-UA-Compatible”content =“ie = edge”>
<TITLE> text5 </ TITLE>
<SCRIPT>
function toDouble(num){
if(num <10){
返回'0'+ num;
} else {
return''+ num;
}
}
window.onload = function(){
var oBtn = document.getElementById('btn');
var aImg = document.getElementsByTagName('img');
var i = 0;
oBtn.onclick = function(){
var oDate = new Date();
var str = toDouble(oDate.getHours())+ toDouble(oDate.getMinutes())+ toDouble(oDate.getSeconds());
for(i = 0; i <aImg.length; i ++){
aImg [i] .src ='img /'+ str.charAt(i)+'。png';
}
};
};
</ SCRIPT>
</ HEAD>
<body style =“color:blue; background:pink; font-size:50px;”>
<input id =“btn”type =“button”value =“更新时间”>
<img src =“img / 0.png”>
<img src =“img / 0.png”>点
<img src =“img / 0.png”>
<img src =“img / 0.png”>分
<img src =“img / 0.png”>
<img src =“img / 0.png”>秒
</ BODY>
</ HTML>
改善:
我们这个时钟是写了一个按钮的,那我总不能时时刻刻去点击这个按钮,那我们就请一个它来帮我点(定时器),去掉按钮,设置一个间隔型的定时器。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>text5</title>
<script>
function toDouble(num) {
if (num < 10) {
return '0' + num;
} else {
return '' + num;
}
}
window.onload = function() {
var oBtn = document.getElementById('btn');
var aImg = document.getElementsByTagName('img');
var i = 0;
function change() {
var oDate = new Date();
var str = toDouble(oDate.getHours()) + toDouble(oDate.getMinutes()) + toDouble(oDate.getSeconds());
for (i = 0; i < aImg.length; i++) {
aImg[i].src = 'img/' + str.charAt(i) + '.png';
}
};
setInterval(change, 1000)
// 特点:等一秒钟过去之后才调用change函数,这时就会有一个小问题,页面先出先全零的情况
change();
// 在页面加载完,就调用一次时间更新的动作
};
</script>
</head>
<body style="color:blue;background: pink;font-size:50px;">
<!-- <input id="btn" type="button" value="更新时间"> -->
<img src="img/0.png">
<img src="img/0.png"> 点
<img src="img/0.png">
<img src="img/0.png"> 分
<img src="img/0.png">
<img src="img/0.png"> 秒
</body>
</html>