前端BOM操作常用命令详解及代码案例_Javascript

前言

bom（browser object model）是浏览器对象模型，是浏览器提供的javascript操作浏览器的api。bom提供了与网页无关的浏览器的功能对象，虽然没有正式的标准，但现代浏览器已经几乎实现了javascript交互性方面的相同方法和属性，因此常被认为是bom的方法和属性。本文将详细介绍bom操作中的常用命令，并通过代码案例进行解释。

1. 获取浏览器窗口尺寸

获取可视窗口宽度：window.innerwidth
获取可视窗口高度：window.innerheight

<!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>document</title>
</head>
<body>
    <script>
        var m1 = window.innerwidth;
        var m2 = window.innerheight;
        console.log(m1);
        console.log(m2);
    </script>
</body>
</html>

2. 浏览器的弹出层

提示框：window.alert('提示信息')
询问框：window.confirm('提示信息')
输入框：window.prompt('提示信息', '默认值')

<!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>document</title>
</head>
<body>
    <script>
        // window.alert('你好!')
        // var res = window.confirm('你好吗?')
        // console.log(res)
        var res2 = window.prompt('你是哪个省的?');
        console.log(res2);
    </script>
</body>
</html>

3. 开启和关闭标签页

开启：window.open('地址')
关闭：window.close()

<!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>document</title>
</head>
<body>
    <button id="on">开启</button>
    <button id="off">关闭</button>
    <script>
        var on = document.getelementbyid('on');
        var off = document.getelementbyid('off');
        on.onclick = function() {
            window.open('https://www.baidu.com/');
        }
        off.onclick = function() {
            window.close();
        }
    </script>
</body>
</html>

4. 浏览器常见事件

资源加载完毕：window.onload = function() {}
可视尺寸改变：window.onresize = function() {}
滚动条位置改变：window.onscroll = function() {}

<!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>document</title>
</head>
<body>
    <img src="图片链接" alt="">
    <script>
        window.onload = function() {
            console.log('资源已经加载完毕');
        }
        window.onresize = function() {
            console.log('可视尺寸改变');
        }
        window.onscroll = function() {
            console.log('滚动条位置改变');
        }
    </script>
</body>
</html>

5. 浏览器的历史记录操作

回退页面：window.history.back()
前进页面：window.history.forward()
跳转到指定页面：window.history.go(n)，其中n可以是负数（表示后退）或正数（表示前进）

<!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>document</title>
</head>
<body>
    <button onclick="goback()">回退</button>
    <button onclick="goforward()">前进</button>
    <button onclick="gotopage(-2)">回退两页</button>
    <script>
        function goback() {
            window.history.back();
        }
        function goforward() {
            window.history.forward();
        }
        function gotopage(n) {
            window.history.go(n);
        }
    </script>
</body>
</html>

6. 浏览器卷去的尺寸和滚动

卷去的高度：document.documentelement.scrolltop 或 window.scrolly
卷去的宽度：document.documentelement.scrollleft 或 window.scrollx
滚动到指定位置：window.scrollto(left, top) 或 window.scrollto({left: xx, top: yy, behavior: 'smooth'})

<!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>document</title>
    <style>
        body {
            width: auto;
            height: 3000px;
        }
        button {
            position: fixed;
            bottom: 50px;
            right: 50px;
        }
    </style>
</head>
<body>
    <button id="go">传送</button>
    <script>
        var go = document.getelementbyid('go');
        go.onclick = function() {
            window.scrollto({left: 300, top: 400, behavior: "smooth"});
        }
    </script>
</body>
</html>

7. navigator对象

navigator对象包含有关浏览器的信息。

<!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>document</title>
</head>
<body>
    <script>
        console.log('浏览器品牌', navigator.appname);
        console.log('浏览器版本', navigator.appversion);
        console.log('用户代理', navigator.useragent);
        console.log('操作系统', navigator.platform);
    </script>
</body>
</html>