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>