JSFiddle - React, Tailwind, and code Playground

by Daedalus

HTML

<input type="text" id="InputOne" onChange="validate()" />

JavaScript

var letterMap = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "S"];

function validate() {
    var value = document.getElementById("InputOne").value;
    if (contains(letterMap, value)) { //

    } else {
        document.getElementById("InputOne").value = "";
    }
}

function contains(array, target) {
    target = target.toUpperCase();
    for (var i = 0; i < array.length; i++) {
        var arrayvalue = array[i];

        if (arrayvalue === target) {
            return true;
        }
    }
    return false;
}