JSFiddle - React, Tailwind, and code Playground

HTML

Click on me: <input id="placeholderText" type="text" class="initialClass" />

CSS

.initialClass {
    color: #999999;
}

.normalClass {
    color: #000000;
}

JavaScript

$(function() {
    $('#placeholderText').val("Placeholder")
        .focusin(function(){
            if($(this).hasClass('initialClass'))
                $(this).removeClass('initialClass').
                    addClass('normalClass').val('');                
        })
        .focusout(function(){ 
            if($(this).hasClass('normalClass') && $(this).val() == '')
                $(this).removeClass('normalClass').
                    addClass('initialClass').val('Placeholder');    
        });
});