was SUPPOSED to be a resize function. Useless, but just saving it.

// in css:
/* Display line under clicked navbar link */
.active {
  text-decoration-line: underline !important;
  text-decoration-thickness: 2px !important;
  color: rgb(20, 19, 19);
}

//in html: 
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>

    <script>
      $(document).ready(function () {
        // Underline to remain in navbar after click using URL
        jQuery(function ($) {
          var path = window.location.href; // because the 'href' property of the DOM element is the absolute path
          $('.nav-link').each(function () {
            if (this.href === path) {
              $(this).addClass('active');
            }
          });
        });
      });
    </script>

//Note class in link should be nav-link

$.ajax({
  type: "POST",
  url: url,
  data: data,
  success: success,
  dataType: dataType
});

This method gets vowels (‘a’, ‘e’, ‘i’, ‘o’, ‘u’) found in a string.
   
#make a function:
def get_vowels(string):

#return is the keyword which means function have to return value: 
 return [each for each in string if each in 'aeiou']


#assign the words and function will return vowels words.
get_vowels('foobar') # ['o', 'o', 'a']


get_vowels('gym') # []

var allElements = $("*");

def when(predicate, when_true):
  return lambda x: when_true(x) if predicate(x) else x
  
EXAMPLES
double_even_numbers = when(lambda x: x % 2 == 0, lambda x : x * 2)
double_even_numbers(2) # 4
double_even_numbers(1) # 1

def unfold(fn, seed):
  def fn_generator(val):
    while True: 
      val = fn(val[1])
      if val == False: break
      yield val[0]
  return [i for i in fn_generator([None, seed])]
  
  
EXAMPLES
f = lambda n: False if n > 50 else [-n, n + 10]
unfold(f, 10) # [-10, -20, -30, -40, -50]

$('iframe').attr('src', $('iframe').attr('src'));

// Replace source
$('img').on("error", function() {
  $(this).attr('src', '/images/missing.png');
});

// Or, hide them
$("img").on("error", function() {
  $(this).hide();
});

jQuery.extend({

  getQueryParameters : function(str) {
	  return (str || document.location.search).replace(/(^\?)/,'').split("&").map(function(n){return n = n.split("="),this[n[0]] = n[1],this}.bind({}))[0];
  }

});

(function($) {
    
  var allPanels = $('.accordion > dd').hide();
    
  $('.accordion > dt > a').click(function() {
    allPanels.slideUp();
    $(this).parent().next().slideDown();
    return false;
  });

})(jQuery);

(function() {
    
    var mX, mY, distance,
        $distance = $('#distance span'),
        $element  = $('#element');

    function calculateDistance(elem, mouseX, mouseY) {
        return Math.floor(Math.sqrt(Math.pow(mouseX - (elem.offset().left+(elem.width()/2)), 2) + Math.pow(mouseY - (elem.offset().top+(elem.height()/2)), 2)));
    }

    $(document).mousemove(function(e) {  
        mX = e.pageX;
        mY = e.pageY;
        distance = calculateDistance($element, mX, mY);
        $distance.text(distance);         
    });

})();

<ul>
  <li>one</li>
  <li>two</li>
  <li>three</li>
</ul>

<script type='text/javascript' src='http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js?ver=1.3.2'></script>
<script type='text/javascript' src='/js/jquery.mousewheel.min.js'></script>

<div id="kitten" style="background-image: url(dog.jpg);">
  <img src="/images/kitten.jpg" alt="Kitten" />
</div>