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>

Daily Test with Code Example

HTML
CSS
JavaScript
PHP-MySQL
Which HTML5 tag can be used to embed an external application (SWF, PDF) in web page?
<mark> <embed> <canvas>
<embed src="flash_game.swf" width="450" height="350" />
Which CSS pseudo-element adds a special style to the first line of a text?
:first-letter :before :first-line
#id:first-line {
  font-weight: bold;
  color: blue;
}
Click on the window object property which gets or sets the URL of current page.
window.location window.self window.status
var url = window.location;
alert(url);
Indicate the PHP function used to get the contents of a file or page and store it into a string.
fopen() file_put_contents() file_get_contents()
$homepage = file_get_contents("http://coursesweb.net/");
echo $homepage;
Keep the first Nr IMG tags, Remove all the others

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