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 tag defines the clickable areas inside the image map?
<map> <img> <area>
<img src="image.jpg" usemap="#map1">
<map name="map1">
  <area shape="rect" coords="9, 120, 56, 149" href="#">
  <area shape="rect" coords="100, 200, 156, 249" href="#">
</map>
Which CSS property defines what is done if the content in a box is too big for its defined space?
display overflow position
#id {
  overflow: auto;
}
Click on the event which is triggered when the mouse is positioned over an object.
onclick onmouseover onmouseout
document.getElementById("id").onmouseover = function(){
  document.write("Have Good Life");
}
Indicate the PHP variable that contains data added in URL address after the "?" character.
$_SESSION $_GET $_POST
if(isset($_GET["id"])) {
  echo $_GET["id"];
}
Keep the first Nr IMG tags, Remove all the others

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