How to parse hashtag, mention and URL in a tweet

I was trying to make a simple twitter application. Using jQuery and AJAX, grabbing twits was not that hard. But twitter returns twit in just simple characters. I needed to show the correct link for the mentions and hashtags and also needed to parse the URLs. So, after little search I came up with some Regex to grab it and then I made a simple function to parse twit. I needed such function in javascript as well as PHP. I just want to share that function here.

function parseTwit(str)
{
 //parse URL
 str = str.replace(/[A-Za-z]+://[A-Za-z0-9-_]+.[A-Za-z0-9-_:%&~?/.=]+/g,function(s){  
  return s.link(s);
 });
 //parse user_name
 str = str.replace(/[@]+[A-Za-z0-9_]+/g,function(s){
  var user_name = s.replace('@','');
  return s.link("http://twitter.com/"+user_name);
 });
 //parse hashtag
 str = str.replace(/[#]+[A-Za-z0-9_]+/g,function(s){
  var hashtag = s.replace('#','');
  return s.link("http://search.twitter.com/search?q="+hashtag);
 }); 
 return str;
}

DEMO

Simple regular expressions are used here. But you can use more robust and advanced regular expressions also.
For URL

/[A-Za-z]+://[A-Za-z0-9-_]+.[A-Za-z0-9-_:%&~?/.=]+/g

For Mention

/[@]+[A-Za-z0-9_]+/g

For Hashtag

/[#]+[A-Za-z0-9_]+/g

Same output can also be obtained from PHP in server side.

function parseTwit($str)
{
 $patterns = array();
 $replace = array();
 //parse URL
 preg_match_all("/[A-Za-z]+://[A-Za-z0-9-_]+.[A-Za-z0-9-_:%&~?/.=]+/",$str,$urls); 
 foreach($urls[0] as $url)
 {
  $patterns[] = $url;
  $replace[] = '<a href="'.$url.'" >'.$url.'</a>';
 } 
 //parse hashtag
 preg_match_all("/[#]+([a-zA-Z0-9_]+)/",$str,$hashtags);
 foreach($hashtags[1] as $hashtag)
 {
  $patterns[] = '#'.$hashtag;
  $replace[] = '<a href="http://search.twitter.com/search?q='.$hashtag.'" >#'.$hashtag.'</a>';
 }
 //parse mention
 preg_match_all("/[@]+([a-zA-Z0-9_]+)/",$str,$usernames);
 foreach($usernames[1] as $username)
 {
  $patterns[] = '@'.$username;
  $replace[] = '<a href="http://twitter.com/'.$username.'" >@'.$username.'</a>';
 }
 //replace now
 $str = str_replace($patterns,$replace,$str);
 //
 return $str;
 
}

PHP function preg_match_all matches the regular expression globally and it is similar to /g modifier. All the matches and to be replaced values are saved in the array. After parsing all, those findings are replaced at once by str_replace function.
Img src : hughlashbrooke