It’s jQuery, and you can add an event when the element is displayed in the window.
I will introduce it because it was very convenient because it could be applied in various ways.
jQuery plugin: jquery.inview
It’s very easy to use.
<script src="https://code.jquery.com/jquery-3.5.1.min.js" integrity="sha256-9/aliU8dGd2tb6OSsuzixeV4y/faTqgFtohetphbbj0=" crossorigin="anonymous"></script>
<script src="../jquery.inview.min.js" />
・・・
// code
$(function() {
$('.inview').on('inview', function(event, isInView) {
if (isInView) {
// element is now visible in the viewport
} else {
// element has gone out of viewport
}
});
});
In the above example, the event will be fired when the element for which class inview is specified is displayed on the screen. It is OK to write briefly as follows.
$('.inview').on('inview', function(){
$(this).addClass('active');
});
The above example adds class active to the displayed element.
It is convenient because it can be animated when it is displayed and has various uses.