jQuery implementation code to determine whether the element exists and then load the content as needed

During the front-end development process, we will use a lot of jQuery plug-ins. If jQuery plug-ins are used too much, it will cause the web page to open slowly. The jQuery plug-in introduced is not required for every page. At this time, using the on-demand loading method to load the jQuery plug-in will be of great help to improve the front-end performance. There are many methods to load on demand. Today we will talk about the jQuery method. How to determine whether an element in a web page exists:

var $selector = $('.my-element');
if ( $ &gt; 0 ) {
  // If it exists, import the jQuery library or do other operations}

Here, let’s first determine whether the page has `.slideshow`. If so, it means that there are slides on this page. We load the jQuery slide plug-in.

var $slideshow = $('.slideshow');
if ( $ > 0 ) {
  $.getScript("js/").done(function() {
  $();
 });
}

If you need to use it frequently, we can also write a function function:

 = function(){ return  &gt; 0; }
 
if ( $(selector).exists() ) {
  // If it exists, import the jQuery library or do other operations}

In some cases where there are many requirements for page effects, the above method can reduce the loading speed of a certain page to a certain extent, thereby improving the user experience.