web页面放到手机页面，缩放问题

有时候写页面样式不规范，很多页面元素写死尺寸时，web页面尺寸比较大放到移动端访问时，就背缩放了，div或者按钮变得好小

可以加段js，效果会好点

 <script>
 ! function( userAgent ) {
     var screen_w = parseInt(window.screen.width),
         scale = screen_w / 640;
     if ( /Android (\d+\.\d+)/.test( userAgent ) ) {
         var version = parseFloat( RegExp.$1 );
         document.write( version > 2.3
             ? '<meta name="viewport" content="width=640, minimum-scale = ' + scale + ", maximum-scale = " + scale + ', target-densitydpi=device-dpi">'
             : '<meta name="viewport" content="width=640, target-densitydpi=device-dpi">' );
     } else {
         document.write( '<meta name="viewport" content="width=640, user-scalable=no, target-densitydpi=device-dpi">' );
     }
 }( navigator.userAgent );

 </script>