JSFiddle - React, Tailwind, and code Playground

HTML

<div>Enter <b>stephen</b> into the input to see change.</div>
 <input type="text" name="carr" id="carr"value="">

CSS

input{
    color:#fff;
    font-weight:bold;
    padding:7px;
    font-size:16px;
    background-color:#FA0000;
}
input.green{
    background-color:#479E00;
    color:#fff;
    font-weight:bold;
}

JavaScript

$( document ).ready(function() {
    
    
    $( "#carr" ).keyup(function() {
    var get_value = $("#carr").val();
        
            if(get_value == "stephen"){
        $("#carr").addClass('green');
    }
});
    
    
    
    });