- 完全自适应的布局可以设置 viewport 为：
<meta name="viewport" content="width=device-width,initial-scale=1">
- 指定具体宽度时如考虑较小分辨的设备，可按设计宽度的一半设置 viewport 如：
<meta name="viewport" content="width=320">
- 指定具体宽度时不考虑较小分辨的设备，直接按设计宽度设置 viewport 如：
<meta name="viewport" content="width=640,user-scalable=0,target-densitydpi=device-dpi">
- 兼容性:
if (/Android (\d+\.\d+)/.test(navigator.userAgent)) {
var version = parseFloat(RegExp.$1);
if (version > 2.3) {
var phoneScale = parseInt(window.screen.width) / 480;
document.write('<meta name="viewport" content="width=480, minimum-scale = ' + phoneScale + ', maximum-scale = ' + phoneScale + ', target-densitydpi=device-dpi">');
} else {
document.write('<meta name="viewport" content="width=480, target-densitydpi=device-dpi">');
}
} else {
document.write('<meta name="viewport" content="width=480, user-scalable=no, target-densitydpi=device-dpi">');
}
see more: mozilla docs
