jQuery addClass example

Change class name on click in jQuery

HTML

<div class="question">
    <h3>
        А я могу ездить на Mercedes S-Class без прав?
            <img src="https://openclipart.org/image/2400px/svg_to_png/154963/1313159889.png" alt="" class="down">
            <img src="https://openclipart.org/image/2400px/svg_to_png/154969/1313159942.png" alt="" class="up">
    </h3>
    <div class="answer">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit. Suscipit aspernatur, consectetur amet mollitia quasi sint provident, totam ad facere quia cumque magnam quisquam culpa praesentium aperiam qui voluptatem maxime corporis.
    </div>
</div>

CSS

img {
  width:1rem;
  height:1rem;
}

JavaScript

$("img.up").hide();

$(".question h3").click(function(){

    var b = $(this);

    var a = b.parent(".question").children(".answer");
    var isVisible = a.css('display') == 'block';

    a.slideToggle();
     
    if(isVisible){
        b.children("img.down").hide();
        b.children("img.up").show()
    } else {
        b.children("img.up").hide();
        b.children("img.down").show()
    };

});