摘要：<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>隨機(jī)</title> <style type="text/css" media="screen"
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>隨機(jī)</title>
<style type="text/css" media="screen">
.box {}
.boxinput {width: 500px;height: 400px;margin: 0px auto;background: #ccc;line-height: 30px;}
}
.boxinput input {margin-left:10px;background: lin}
.boxP {color:#222;width: 400px;margin: 0px auto;}
</style>
</head>
<body>
<div class="box">
<div class="boxinput">
<input type="checkbox" name=""><span>one</span><br>
<input type="checkbox" name=""><span>two</span><br>
<input type="checkbox" name=""><span>three</span><br>
<input type="checkbox" name=""><span>four</span><br>
<button type="button" onclick="checkaall()">全選</button>
<button type="button" onclick="bgc()">換背景色</button>
<button type="button" onclick="clearInterval(t) ">停止倒計(jì)時(shí)</button>
<!-- clearInterval 函數(shù)是清除倒計(jì)時(shí) -->
</div>
<div class="boxP">
10 秒后跳轉(zhuǎn) 到 我愛linux網(wǎng)www.52linux.cn
</div>
</div>
<script type="text/javascript">
//全選
function checkaall() {
var boxinput = document.getElementsByClassName('boxinput')[0].getElementsByTagName('input')
for (var i=0;i<boxinput.length;i++) {
if (boxinput[i].checked){ //如果選中就取消
boxinput[i].checked=false
}else{ //如果沒有選中就勾選
boxinput[i].checked=true
}
}
}
//換背景
function bgc() {
var r = Math.round(Math.random()*(255-0))+0
var g = Math.round(Math.random()*(255-0))+0
var b = Math.round(Math.random()*(255-0))+0
var ap = Math.random()
var apstr = ap.toString() //轉(zhuǎn)字符串
var apstr =apstr.slice(0,3) //字符串截取
var f = Math.round(Math.random()*(30-12))+12
console.log()
var rgb1 = "rgba(" + r + "," + g + "," + b + ","+apstr+")"
console.log(rgb1)
document.getElementsByClassName('boxinput')[0].style.background=rgb1
// boxinput[0]//"rgb("+r","+g+","+b+")"
}
//倒計(jì)時(shí)
function jishi(){
var boxP = document.getElementsByClassName('boxP')[0]
var num = parseInt(boxP.innerHTML)
console.log(num)
if (num<1){
window.location.href="http://www.linuxup.cn"
} else {
boxP.innerHTML=num-1+"秒后跳轉(zhuǎn) 到 我愛linux網(wǎng)www.52linux.cn"
}
}
var t =setInterval("jishi()", 1000)
</script>
</body>
</html>
批改老師：天蓬老師批改時(shí)間：2019-04-20 13:39:41
老師總結(jié)：JavaScript允許省略語句后臺(tái)的分號(hào), 這個(gè)風(fēng)格曾經(jīng)有一段時(shí)間非常的流行, 不過, JS的開發(fā)者已經(jīng)站出來澄清了, 強(qiáng)烈不建議省略掉語句后的分號(hào), 以防止壓縮代碼時(shí)出錯(cuò), 所以, 以后, 還是要添加分號(hào)的