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
What attribute makes the input text box to not be modified by the user?
checked="checked" readonly="readonly" disabled="disabled"
<input type="text" value="fixed-value" readonly="readonly" name="a_name" />
What CSS property allows you to create rounded corners in your webpage design?
background-size border-size border-radius
.class {
  border:2px solid blue;
  border-radius:1.2em;
}
What instruction displays a confirmation dialog box to the viewer, who must then click OK or Cancel to proceed?
indexOf() confirm() prompt()
var ques = window.confirm("The result of 0+0 is 0?");
if (ques) alert("Corect");
else alert("Incorrect");
Indicate the PHP function that returns the lowest number of the parameter values.
floor() ceil() min()
$min_nr = min(12, 8, 25, 13);
echo $min_nr;        // 8
Keep the first Nr IMG tags, Remove all the others

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