Add Class

<script>
(function($){
  jQuery(document).ready(function($) {
$( window ).on('scroll', function(){

      $(".acc-section-3 .bg-overlay-image").addClass("fade-up");
});
    });
})(jQuery);
</script>

Add Attribute with value

<script>
(function($){
  jQuery(document).ready(function($) {
$( window ).on('load', function(){

      $(".gallery-items figure img").attr("data-aos", "zoom-in");
});
    });
})(jQuery);
</script>



<script>
$( "img" ).attr({
  src: "/resources/hat.gif",
  title: "jQuery",
  alt: "jQuery Logo"
});
$( "div" ).text( $( "img" ).attr( "alt" ) );
</script>

Remove Attributes

<script>
(function($){
  jQuery(document).ready(function($) {
$( window ).on('load', function(){

      $(".gallery-items figure img").removeAttr("loading");
});
    });
})(jQuery);
</script>


    <!-- jQuery code to show the working of this method -->
    <script>
        $(document).ready(function () {
            $("button").click(function () {
                $("p").removeAttr("style");
            });
        });
    </script>

Set the src attribute from title attribute on the image. 

<img title="hat.gif">
 
<script>
$( "img" ).attr( "src", function() {
  return "/resources/" + this.title;
});
</script>