PHP code to detect whether the URL address and http address format are valid

/**
 desc: Check whether the network address format is valid
 link: bbs.it-home.org
 date: 2013/2/24
*/
function checkUrl($weburl)
{
 return !ereg("^http(s)*://[_a-zA-Z0-9 -]+(.[_a-zA-Z0-9-]+)*$", $weburl);
} ?>

2. Determine whether the http address is valid

/**
 desc: Check whether the http address is valid
 link: bbs.it-home.org
 date: 2013/2/24
*/
function url_exists($url)
{
 $ch = curl_init();
 curl_setopt($ch, CURLOPT_URL,$ url);
 curl_setopt($ch, CURLOPT_NOBODY, 1); // Do not download
 curl_setopt($ch, CURLOPT_FAILONERROR, 1);
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
 return (curl_exec($ch)!= =false) ? true : false;
}
//Method 2
function img_exists($url)
{
 return file_get_contents($url,0,null,0,1) ? true : false;
}
//Method 3:
function url_exists($url)
{
 $head = @get_headers($url);
 return is_array($head) ? true : false;
} ?>

Call example:

 $url='http://bbs.it-home.org';
 echo url_exists($url);
?>