1 html{
2 font-size:12px;
3 }
4 .btn {
5 width: 6rem;
6 height: 3rem;
7 line-height: 3rem;
8 font-size: 2rem;
9 display: inline-block;
10 background: #06c;
11 color: #fff;
12 border-radius: .5rem;
13 text-decoration: none;
14 text-align: center;
15 }
16 .p{font-size: 2rem;}
17 </style>
18 <script>
19 alert("ddd");
20 document.getElementsByTagName('html')[0].style.fontSize = "20px";
21 alert(document.getElementsByTagName('html')[0].style.fontSize);
22
23 //1.6rem*window.innerWidth / 320 + 'px';
24 </script>
25 </header>
26 <body>
27
28 <div>
29 qwertyuiop
30 <p class="p">yyyyyy</p>
31 <button class="btn"> click </button>
32 </div>
33
34 </body>
35 </html>
