php常用自建函数学习(5):判断是否是通过手机访问

/**
*判断是否是通过手机访问
*/
if(!function_exists('isMobile'))
{
	function IsMobile()
	{
	
		//如果有HTTP_X_WAP_PROFILE则一定是移动设备
		if(isset($_SERVER['HTTP_X_WAP_PROFILE']))  return TRUE;
	
		//如果via信息含有wap则一定是移动设备,部分服务商会屏蔽该信息
		if(isset($_SERVER['HTTP_VIA']))
		{
			//找不到为flase,否则为true
			return stristr($_SERVER['HTTP_VIA'], "wap") ? true : false;
		}
	
		//判断手机发送的客户端标志,兼容性有待提高
		if(isset($_SERVER['HTTP_USER_AGENT']))
		{
	
			$clientkeywords = array('nokia','sony','ericsson','mot','samsung','htc','sgh','lg','sharp','sie-','philips','panasonic','alcatel','lenovo','iphone','ipod','blackberry','meizu','android','netfront','symbian','ucweb','windowsce','palm','operamini','operamobi','openwave','nexusone','cldc','midp','wap','mobile');
	
			//从HTTP_USER_AGENT中查找手机浏览器的关键字
			if(preg_match('/('.implode('|', $clientkeywords).')/i', strtolower($_SERVER['HTTP_USER_AGENT'])))
			{
				return TRUE;
			}
		}
	
		//协议法，因为有可能不准确，放到最后判断
		if(isset($_SERVER['HTTP_ACCEPT']))
		{
			//如果只支持wml并且不支持html那一定是移动设备
			//如果支持wml和html但是wml在html之前则是移动设备
			if((strpos($_SERVER['HTTP_ACCEPT'], 'vnd.wap.wml') !== false) &&
			   (strpos($_SERVER['HTTP_ACCEPT'], 'text/html') === false ||
			   (strpos($_SERVER['HTTP_ACCEPT'], 'vnd.wap.wml')