private function is_mobile()
{
	//正则表达式,批配不同手机浏览器UA关键词。
	$regex_match="/(nokia|iphone|android|motorola|^mot\-|softbank|foma|docomo|kddi|up\.browser|up\.link|";
	$regex_match.="htc|dopod|blazer|netfront|helio|hosin|huawei|novarra|CoolPad|webos|techfaith|palmsource|";
	$regex_match.="blackberry|alcatel|amoi|ktouch|nexian|samsung|^sam\-|s[cg]h|^lge|ericsson|philips|sagem|wellcom|bunjalloo|maui|";
	$regex_match.="symbian|smartphone|midp|wap|phone|windows ce|iemobile|^spice|^bird|^zte\-|longcos|pantech|gionee|^sie\-|portalmmm|";
	$regex_match.="jig\s browser|hiptop|^ucweb|^benq|haier|^lct|opera\s*mobi|opera\*mini|320x320|240x320|176x220";
	$regex_match.=")/i";

	return isset($_SERVER['HTTP_X_WAP_PROFILE']) or isset($_SERVER['HTTP_PROFILE']) or preg_match($regex_match, strtolower($_SERVER['HTTP_USER_AGENT'])); 
	//如果UA中存在上面的关键词则返回真。
}