利用rem實現響應式佈局
阿新 • • 發佈:2018-12-23
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width,initial-scale=1.0,maximum-scale=1.0,user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<!--<meta name="apple-mobile-web-app-status-bar-style" content="black">-->
<meta name="format-detection" content="telephone=no">
<title></title>
<link rel="stylesheet" type="text/css" href="css/channel.css" />
<script type="text/javascript">
(function(designWidth, maxWidth) {
var doc = document,
win = window,
docEl = doc.documentElement,
remStyle = document.createElement("style"),
tid;
function refreshRem() {
var width = docEl.getBoundingClientRect().width;
maxWidth = maxWidth || 540;
width > maxWidth && (width = maxWidth);
var rem = width * 100 / designWidth;
remStyle.innerHTML = 'html{font-size:' + rem + 'px;}';
}
if(docEl.firstElementChild) {
docEl.firstElementChild.appendChild(remStyle);
} else {
var wrap = doc.createElement("div");
wrap.appendChild(remStyle);
doc.write(wrap.innerHTML);
wrap = null;
}
//要等 wiewport 設定好後才能執行 refreshRem,不然 refreshRem 會執行2次;
refreshRem();
win.addEventListener("resize", function() {
clearTimeout(tid); //防止執行兩次
tid = setTimeout(refreshRem, 300);
}, false);
win.addEventListener("pageshow", function(e) {
if(e.persisted) { // 瀏覽器後退的時候重新計算
clearTimeout(tid);
tid = setTimeout(refreshRem, 300);
}
}, false);
if(doc.readyState === "complete") {
doc.body.style.fontSize = "16px";
} else {
doc.addEventListener("DOMContentLoaded", function(e) {
doc.body.style.fontSize = "16px";
}, false);
}
})(750, 750);
</script>
</head>