JSFiddle - React, Tailwind, and code Playground

HTML

<div id="preview1">111111</div>
<div id="preview2">222222</div>

<input type="button" value="Click Me" />

CSS

div {
    WIDTH: 40%;
    height: 30px;
    margin: 1em;
}
#preview1 {
    border: 1pt blue solid;
}
#preview2 {
    border: 1pt red solid;
    display:none;
}

JavaScript

$("input").click(function(){
    if($('#preview1').is(':visible'))
    //if($('#preview1').css('opacity',1))
    {
        $('#preview1').fadeOut();
        fnBuildPrev('#preview2');
        $('#preview2').fadeIn();
    }
    else
    {
        $('#preview2').fadeOut();
        fnBuildPrev('#preview1');
        $('#preview1').fadeIn();
    }
});