Shorten URL text on links like stackoverflow?

My guess would be that you just have to search for <a> tags in your source output, and change it's value accordingly. href stays the same, but you change the link name to what you want.

But that's just one idea... You can always experiment with new stuff.

There should also be a way to accomplish this with javascript on-the-go.

Think out of the box!

Here is a function to replace URLs with links. You will just need to adjust how you want to format it. Maybe use parse_url()

<?php
function URLref($sentence){
  $temp = explode(" ", $sentence);
  $new = "";
  foreach($temp as $i){
    if(preg_match('([A-Za-z][A-Za-z0-9+.-]{1,120}:[A-Za-z0-9/](([A-Za-z0-9$_.+!*,;/?:@&~=-])|%[A-Fa-f0-9]{2}){1,333}(#([a-zA-Z0-9][a-zA-Z0-9$_.+!*,;/?:@&~=%-]{0,1000}))?)', $i)){
      $new .= '<a href="'.$i.'">'.$i.'</a>';
    }else{
      $new .= "$i ";
    }
  }
  return trim($new);
}
$sentence = "My site ULR is http://www.google.com/lolz.html";

echo URLref($sentence);

You could retrieve URLs using regular expressions, here two examples on how to create <a> tags from found URLs and on how to shorten content of <a> tags:

<?php

$orig_text = <<<TEXT
This is some text. http://www.example.com/this-is-a-quite-long-url-to-be-shortened.html
http://www.example.com/another-url-to-be-shortened and http://www.example.com/another-one-that-is-longer-than-limit then
http://www.example.com/an-ok-url and some text to finish the sentence.

Now, try with an HTTPS url: https://www.example.com/this-https-url-is-too-long.

And with an already-created tag <a href='http://www2.example.com/this-is-another-long-url.html'>http://www2.example.com/this-is-another-long-url.html</a> <a href='http://www2.example.com/my-test-url-goes-here.html'>And this is just some long long link description to be shortened</a>. More text here.

TEXT;

$PATTERN_URL='#(?:href=[\'"]?)?!(https?://([^/]+)/([^\s]+))\b#';
define('URL_LENGTH_LIMIT', 36);

function create_a_tag($matches) {
  $url = $matches[1];
  $label = $matches[1];
  if (strlen($label) > URL_LENGTH_LIMIT) $label = $matches[2] . '/...';
  return "<a href='$url'>$label</a>";
}

function shorten_url_or_text($url) {
  if (strlen($url) > URL_LENGTH_LIMIT) {
    $matches = array();
    if (preg_match('#^(https?://[^/]*).*#', $url, $matches)) {
      // Shorten as for URLS
      return $matches[1] . '/...';
    }
    else {
      // Trim to a given length
      return substr($url, 0, URL_LENGTH_LIMIT-3) . '...';
    }
  }
  else {
    return $url;
  }
}

function shorten_a_text($matches) {
  $text = shorten_url_or_text($matches[2]);
  return $matches[1] . $text . $matches[3];
}

// This will replace urls with their shortened form
echo "----- CREATE <A> TAGS -----\n";
$text2 = preg_replace_callback($PATTERN_URL, 'create_a_tag', $orig_text);
echo $text2 . "\n";

// This will shorten content inside <a> tags
echo "----- CREATE <A> TAGS -----\n";
$text3 = preg_replace_callback('@(<a[^>]*>)([^<]*)(</a>)@i', 'shorten_a_text', $text2);
echo $text3;
echo "\n";