JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" placeholder="valid:abc" autofocus="true" />

CSS

input {
    padding:2%;
    box-shadow:1px 1px 1px rgba(0, 0, 0, 0.5);
    border:0;
    outline:0;
    border:1px solid lightgrey;
}

JavaScript

input = document.querySelector("input");
restrictChars(input, "abc");

function restrictChars(input, chars) {
    input.addEventListener("keypress", function (e) {
        e.preventDefault();
        var character = String.fromCharCode(e.keyCode);
        var isValid = chars.indexOf(character) != -1;
        if (isValid) {
            input.value += character;
        }
    });
}