if(/Android (\d+\.\d+)/.test(navigator.userAgent)){
      var version = parseFloat(RegExp.$1);
      if(version>2.3){
        var phoneScale = parseInt(window.screen.width)/640;
        document.write('<meta name="viewport" content="width=640, minimum-scale = '+ phoneScale +', maximum-scale = '+ phoneScale +', target-densitydpi=device-dpi">');
      }else{
        document.write('<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">');
    }