JSFiddle - React, Tailwind, and code Playground

HTML

<div id="A">Visible</div>
<div id="B">hidden</div>

CSS

#A {
    width:400px;
    height:50px;
    background-color:green;
}
#B {
    width:400px;
    height: 150px;
    background-color:pink;
    opacity: 0;
}

JavaScript

$('#B').on({
    mouseover: function() {
        $(this).fadeTo(1,1);
    },mouseleave: function() {
        $(this).fadeTo(1,0);
    },click: function() {
        $(this).off('mouseleave');
    }
});