JSFiddle - React, Tailwind, and code Playground

HTML

<input id="test">

JavaScript

function isKeypressCharValid(e, chars) {
    e = e || window.event;

    // Allow delete, escape, tab and enter
    if (/^(8|9|13|27)$/.test("" + e.keyCode)) {
        return true;
    }
    
    var charCode = (typeof e.which == "number") ? e.which : e.keyCode;
    var charTyped = String.fromCharCode(charCode);
    return chars.indexOf(charTyped) > -1;
}


var textBox = document.getElementById("test");

textBox.onkeypress = function(evt) {
    if (!isKeypressCharValid(evt, "abc123")) {
        return false;
    }
};