<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no, target-densitydpi=device-dpi" />
http://www.cnblogs.com/bugs/archive/2013/06/17/3139811.html
腾讯：
<meta name="viewport" content="width=100%, initial-scale=1.0, user-scalable=no"/>
第一：
<meta name="viewport" content="width=device-width, initial-scale=1">