vw rem 根据页面宽度来设置根字号 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1, user-scalable=no">
    <title>Document</title>
    <style>
        html,body{
            font-size:13.33333333vw;
        }
        @media screen and (min-width :750px){
            html,body{
                font-size:100px;
                background-color:skyblue;
            }
        }
        @media screen and (max-width :320px){
            html,body{
                font-size:42.666666px;
                background-color:pink;
            }
        }
        body{
            max-width:750px;
            margin:auto;
            background-color: #eee;
        }
        .fs{
            width:100rem;
            font-size: 0.24rem;
        }
    </style>
</head>
<body>
    <div class="fs">主题</div>
</body>
</html>

原理：

(function(doc, win) {


	var docEl = doc.documentElement,
		resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
		recalc = function() {
			var clientWidth = docEl.clientWidth;
			if(!clientWidth) return;
			if(clientWidth >= 750) {
				docEl.style.fontSize = '100px';
			} else {
				//docEl.style.fontSize = 100 * (clientWidth / 640) + 'px';
				docEl.style.fontSize = clientWidth / 7.5 + 'px';
			}
		};

	if(!doc.addEventListener) return;
	win.addEventListener(resizeEvt, recalc, false);
	doc.addEventListener('DOMContentLoaded', recalc, false);
})(document, window);

　　

posted @ 2020-11-10 13:44  牧唐丫  阅读(134)  评论(0)  编辑  收藏  举报