<?php if(strpos($_SERVER['HTTP_USER_AGENT'],"iPhone")){?>
  <meta name="viewport" content="initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.0">
 <?php }else if(strpos($_SERVER['HTTP_USER_AGENT'],"iPad")){?>
  <meta name="viewport" content="user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, width=device-width" />
 <?php }else if(strpos($_SERVER['HTTP_USER_AGENT'],"Android 4")){?>
  <meta name="viewport" content="initial-scale=1.0; maximum-scale=1.0; minimum-scale=1.0; user-scalable=no" />
 <?php }else if(strpos($_SERVER['HTTP_USER_AGENT'],"Android 2")){?>
  <meta name="viewport" content="initial-scale=1.0; maximum-scale=1.0; minimum-scale=1.0; user-scalable=no" />
 <?php }else if(strpos($_SERVER['HTTP_USER_AGENT'],"Android")){?>
  <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0" />
 <?php }else if(strpos($_SERVER['HTTP_USER_AGENT'],"Opera Mini")){?>
  <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" />
 <?php }else if(strpos($_SERVER['HTTP_USER_AGENT'],"Opera 9")){?>
  <meta name="viewport" content="initial-scale=0.75, maximum-scale=0.75, minimum-scale=0.75, user-scalable=no" />
 <?php }else if(strpos($_SERVER['HTTP_USER_AGENT'],"MSIE")){?>
  <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" />
 <?php }else if(strpos($_SERVER['HTTP_USER_AGENT'],"FROYO")){?>
  <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" />
 <?php }?>