php验证URL是否合法的函数

function isValidUrl($url) {
 
    $patern = '/^http[s]?:＼/＼/'.
        '(([0-9]{1,3}＼.){3}[0-9]{1,3}'.             // IP形式的URL- 199.194.52.184
        '|'.                                        // 允许IP和DOMAIN（域名）
        '([0-9a-z_!~*＼'()-]+＼.)*'.                  // 三级域验证- www.
        '([0-9a-z][0-9a-z-]{0,61})?[0-9a-z]＼.'.     // 二级域验证
        '[a-z]{2,6})'.                              // 顶级域验证.com or .museum
        '(:[0-9]{1,4})?'.                           // 端口- :80
        '((＼/＼?)|'.                                 // 如果含有文件对文件部分进行校验
        '(＼/[0-9a-zA-Z_!~＼*＼'＼(＼)＼.;＼?:@&=＼+＼$,%#-＼/]*)?)$/';
 
    if(!preg_match($patern, $url)) {
        die( '您输入的URL格式有问题，请检查！');
    }
}

$url = "http://www.111com.net ";
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_NOBODY, true);
$result = curl_exec($curl);
if ($result !== false)
{
  $statusCode = curl_getinfo($curl, CURLINFO_HTTP_CODE); 
  if ($statusCode == 404)
  {
    echo "URL Not Exists"
  }
  else
  {
     echo "URL Exists";
  }
}
else
{
  echo "URL not Exists";
}