获取访问者IP

function get_ip()
	{
		$clientip = "";
		if(getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown"))
		{
			$clientip = getenv("HTTP_X_FORWARDED_FOR");
		} 
		elseif(getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))
		{
			$clientip = getenv("HTTP_CLIENT_IP");
		} 
		
		elseif(getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown")) 
		{
			$clientip = getenv("REMOTE_ADDR");
		} 
		elseif(isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown"))
		{
			$clientip = $_SERVER['REMOTE_ADDR'];
		}

		preg_match("/[\d\.]{7,15}/", $clientip, $clientipmatches);
		$clientip = $clientipmatches[0] ? $clientipmatches[0] : "unknown";
		return $clientip;
	}