console 命令行工具 X clear

console

function refreshRem() {
    var docEl = document.documentElement;
    var width = docEl.getBoundingClientRect().width;
    width = document.querySelector('body').offsetWidth;
    var rem = width / 120;
    docEl.style.fontSize = rem + 'px';
}
window.addEventListener('resize', refreshRem);

<body>
    <div>你好</div>
    <div style="width: 2rem;height: 2rem;background: red;"></div>
    <div style="font-size: 1.6rem">你好</div>
</body>

body {
    min-width: 500px;
}