一、简介
二、window对象(全局对象)
(1)window.setTimeout()等
我们之前学过的,如setTimeout()方法,其实完整的写法是window.setTimeout()。
<script>
window.setTimeout(() => {
console.log("hello world!")
}, 1000)
</script>
(2)自定义的全局函数(window.fun())
<script>
function fun() {
console.log("hello world");
}
window.fun();
</script>
控制台输出:
(3)window.alert()
<script>
window.alert("hello world");
</script>
(4)window.prompt()
<script>
let str = window.prompt("请输入内容:", "你好!");
console.log(str);
</script>
效果如下:
分析:
(5)window.confirm()
<script>
let result = window.confirm("是否删除该条数据?");
console.log(result);
</script>
效果如下:
分析:
(6)案例一——猜数字
<script>
// 生成【1,100】的随机数
let targetNumber = Math.floor(Math.random() * 100 + 1);
// 递归函数:在函数内部,多次调用该函数
function guessNumber() {
let number = prompt("请输入数字:");
if (number == targetNumber) {
alert("恭喜你回答正确!");
} else if (number > targetNumber) {
alert("大于目标数字,请再猜一次");
guessNumber();
} else if (number < targetNumber) {
alert("小于目标数字,请再猜一次")
guessNumber();
} else {
alert("格式错误,请重新输入!")
guessNumber();
}
}
guessNumber();
</script>
效果如下:
(7)案例二——删除水果的提示框
<body>
<ul>
<li>苹果</li>
<li>鸭梨</li>
<li>香蕉</li>
</ul>
<script>
let ul = document.querySelector("ul");
ul.onclick = function (e) {
let result = confirm("是否删除该水果?")
if (result) {
ul.removeChild(e.target);
}
}
</script>
</body>
效果如下:
分析:
三、location对象
(1)随便打开一个网址,输入各种属性,查看结果。
如:
反ins社交App真的开始默默生长了?https://m.thepaper.cn/baijiahao_17638219并打开控制台,分别输入:
输出如下:
(2)跳转网页(location.href())
<body>
<button>百度</button>
<script>
let btn = document.querySelector("button");
btn.onclick = function () {
location.href = "https://www.baidu.com";
}
</script>
</body>
效果如下:
分析:
四、Navigator(获取访问者的浏览器信息)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Demo35</title>
</head>
<body>
<script>
let equipment = checkagent(navigator.userAgent);
console.log(equipment);
function checkagent(ua) {
let isWindowsPhone = /(?:Windows Phone)/.test(ua),
isSymbian = /(?:SymbianOS)/.test(ua) || isWindowsPhone,
isAndroid = /(?:Android)/.test(ua),
isFireFox = /(?:Firefox)/.test(ua),
isChrome = /(?:Chrome|CriOS)/.test(ua),
isTablet = /(?:iPad|PlayBook)/.test(ua) || (isAndroid && !/(?:Mobile)/.test(ua)) || (isFireFox && /(?:Tablet)/.test(ua)),
isPhone = /(?:iPhone)/.test(ua) && !isTablet,
isPc = !isPhone && !isAndroid && isSymbian,
isWechat = /(?:MicroMessenger)/.test(ua);
let equipment = {
isTablet: isTablet,
isPhone: isPhone,
isAndroid: isAndroid,
isChrome: isChrome,
isPc: isPc,
isWechat: isWechat
};
if (equipment.isAndroid) {
return "安卓手机";
} else if (equipment.isPhone) {
return "苹果手机";
} else if (equipment.isTablet) {
return "平板";
} else if (equipment.isPc) {
return "电脑";
}else if(equipment.isChrome){
return "谷歌浏览器";
}
}
</script>
</body>
</html>
效果如下:
分析: