JSFiddle - React, Tailwind, and code Playground

HTML

<input placeholder="type 'hello'" id="test" type="text" />
<input type="submit" id="byBtn" value="Verifier" onclick="isCorrect()" />

CSS

input[type=text] {
	    padding: 2px;
	    border: 1px solid #CCC;
	    border-radius: 2px;
	    outline: none;
	}
	.correct {
	    background-color: #FF1199
	}
	.incorrect {
	    background-color: #555555
	}

JavaScript

function isCorrect() {
    var test = document.getElementById('test');
    if (test.value === "hello") {
        test.className = "correct";
        return true;
    } else {
        test.className = "incorrect";
        return false;
    }
}