Keep the first Nr IMG tags, Remove all the others

Javascript Course

The keepFirstImgs() function presented in this page can be used in JavaScript to keep the first Nr IMG tags into a string, and Remove all the other <img>s.
- The function receives the number of the first <img> tags to keep (nrimg), and the string with the HTML text (str); returns the string with the other IMG tags removed.

// Function to keep first $nrimg IMG tags in $str, and removes all the other <img>s
// From: https://coursesweb.net/javascript/
var keepFirstImgs = function(nrimg, str) {
  // gets array with the <img>s that must be stripped from $str ($nrimg+), and removes them
  var remove_imgs = str.match(/(\<img[^\>]+\>)/ig).slice(nrimg);
  var nr_i = remove_imgs.length;
  for(var i=0; i<nr_i; i++) str = str.replace(remove_imgs[i], '');
  return str;
}

- Example:

<script type="text/javascript">
// Function to keep first $nrimg IMG tags in $str, and removes all the other <img>s
// From: https://coursesweb.net/javascript/
var keepFirstImgs = function(nrimg, str) {
  // gets array with the <img>s that must be stripped from $str ($nrimg+), and removes them
  var remove_imgs = str.match(/(\<img[^\>]+\>)/ig).slice(nrimg);
  var nr_i = remove_imgs.length;
  for(var i=0; i<nr_i; i++) str = str.replace(remove_imgs[i], '');
  return str;
}

// Test, keeps the first two IMG tags in $str
var str = 'First img: <img src="img1.jpg" alt="img 1" width="30" />,\
 second image: <img src="img_2.jpg" alt="img 2" width="30">,\
 another Img tag <img src="img3.jpg" alt="img 3" width="30" />,\
 and another image <img src="img_4.jpg" alt="imgage 4" width="30" /> ... etc.';

str = keepFirstImgs(2, str);

alert(str);
/* Result:
 First img: <img src="img1.jpg" alt="img 1" width="30" />,
 second image: <img src="img_2.jpg" alt="img 2" width="30">,
 another Img tag , and another image  ... etc.
*/
</script>

<table><tr>
  <th>Title 1</th>
  <th>Title 2</th>
</tr></table>

.some_class {
  line-height: 150%;
}

document.getElementById("id_button").onclick = function(){
  window.open("http://coursesweb.net/");
}

$ar_dir = scandir("dir_name");
var_export($ar_dir);