移动端H5自适应js | 易学教程

第一种方法：

在原生app打开链接的时候，适配不兼容，页面宽度为750px，不是全屏显示。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset=utf-8>
    <meta content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=0" name="viewport">
    <title>Title</title>
    <style>
        .app{ font-size:30px; width: 540px; border: 1px solid #ccc; display: block; margin: 0 auto;}
    </style>
    <script>
        //在原生app打开链接的时候，适配不兼容，页面宽度为750px，不是全屏显示。
         // class
         ! function(navigator) {
            var userAgent = navigator.userAgent;
            documentElement = document.documentElement;
            if(userAgent.match(/micromessenger\/5/gi)) {
                documentElement.className += " mobile wx_mobile wx_mobile_5";
            } else if(userAgent.match(/micromessenger/gi)) {
                documentElement.className += " mobile wx_mobile";
            } else if(userAgent.match(/ucbrowser/gi)) {
                documentElement.className += " mobile uc_mobile";
            } else if(/android|webos|iphone|ipad|ipod|blackberry|iemobile|opera mini/i.test(userAgent.toLowerCase())) {
                documentElement.className += " mobile";
            } else if(userAgent.toLowerCase().match(/msie/gi) && (parseFloat(userAgent.toLowerCase().match(/msie ([0-9]{1,}[\.0-9]{0,})/i)[1] || 999) < 9)) {
                documentElement.className += " pc pc-ie pc-ie8";
            } else if(userAgent.toLowerCase().match(/msie/gi) || navigator.msPointerEnabled || navigator.pointerEnabled) {
                documentElement.className += " pc pc-ie";
            } else {
                documentElement.className += " pc";
            }
        }(navigator);
        // meta
            ! function(userAgent) {
                var screen_w = parseInt(window.screen.width),
                    scale = screen_w / 750;
                if (/Android (\d+\.\d+)/.test(userAgent)) {
                    var version = parseFloat(RegExp.$1);
                    document.write(version > 2.3 ? '<meta name="viewport" content="width=750, minimum-scale = ' + scale + ", maximum-scale = " + scale + ', target-densitydpi=device-dpi">' : '<meta name="viewport" content="width=750,target-densitydpi=device-dpi">');
                } else {
                    document.write('<meta name="viewport" content="width=750, user-scalable=no">');
                }
            }(navigator.userAgent);
    //可以按照设计图宽度的像素直接定义元素单位。
    </script>
</head>
<body>
<div class="app">hello world</div>
</body>
</html>

第二种方法：

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset=utf-8>
        <meta content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=0" name="viewport">
        <title>Title</title>
        <style>
            .app{ font-size:1rem; border:1px solid #ccc;}
            .app2{ font-size:50px;}
        </style>
        <script>
            (function(){
                var currClientWidth,
                    fontValue,
                    originWidth;
                originWidth = 750;//ui设计稿的宽度，一般750或640
                __resize();
        
                window.addEventListener('resize', __resize, false);
        
                function __resize() {
                    currClientWidth = document.documentElement.clientWidth;
                    if (currClientWidth > 768){
                        currClientWidth = 768;
                    }
                    if (currClientWidth < 320){
                        currClientWidth = 320;
                    }
                    fontValue = ((625 * currClientWidth) / originWidth).toFixed(2);
                    document.documentElement.style.fontSize = fontValue + '%';
                }
            })();
            // 当前假如当前分辨率是375， 设计稿分辨率是750
            // 750/375=0.5
            // 比例关系是0.5倍
            // 再算一下你要换算1rem等于多少px，
            // 假如我要100， 100/16=6.25
            // 把这个换算的乘以刚才得出的比例
            // 0.5*625=312.5
            // 最后还拼接了一个百分号 = 312.5%
            // 就是在375分辨率下 1rem = 312.5%
            // 312.5% * 16px = 50px
        </script>
    </head>
    <body>
    <div class="app">hello world</div>
    <div class="app2">hello world</div>
    </body>
    </html>

第三种方法：

利用rem + flexable.js 使html根元素根据页面的缩放，改变文字大小。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no">
    <title>title</title>
    <style>
        .app{ font-size: 1rem; }
        /* 1rem = 100px */
    </style>
    <script>
    (function flexible (window, document) {
    var docEl = document.documentElement
    var dpr = window.devicePixelRatio || 1

    // adjust body font size
    function setBodyFontSize () {
        if (document.body) {
        document.body.style.fontSize = (12 * dpr) + 'px'
        }
        else {
        document.addEventListener('DOMContentLoaded', setBodyFontSize)
        }
    }
    setBodyFontSize();

    // set 1rem = viewWidth / 10
    function setRemUnit () {
        var rem = docEl.clientWidth / 7.5
        if(rem>=100){
        rem = 100
        }else if(rem<=42.6){
        rem = 42.6
        };
        docEl.style.fontSize = rem + 'px'
    }

    setRemUnit()

    // reset rem unit on page resize
    window.addEventListener('resize', setRemUnit)
    window.addEventListener('pageshow', function (e) {
        if (e.persisted) {
        setRemUnit()
        }
    })

    // detect 0.5px supports
    if (dpr >= 2) {
        var fakeBody = document.createElement('body')
        var testElement = document.createElement('div')
        testElement.style.border = '.5px solid transparent'
        fakeBody.appendChild(testElement)
        docEl.appendChild(fakeBody)
        if (testElement.offsetHeight === 1) {
        docEl.classList.add('hairlines')
        }
        docEl.removeChild(fakeBody)
    }
    }(window, document))
    </script>
</head>
<body>
<div class="app">hello world</div>
</body>
</html>

来源：CSDN

作者：Julie薇薇

链接：https://blog.csdn.net/verwei/article/details/89107655

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