JSFiddle - React, Tailwind, and code Playground

by Daedalus

HTML

<button id="make_controls">Click me to make the field</button>
<div id="field_cont"></div>

JavaScript

$(function () {
    $("#make_controls").on("click", function () {
        if ($("#address").length === 0) {
            $("#field_cont").append('<input type="text" id="address" />\
    <button id="button">Disable me by typing in any variant of "PO BOX"</button>');
        }
    });
    $("#field_cont").on("keyup blur", "#address", function () {
        var $this = $(this);
        if ($this.length > 0) {
            if (/p\.?o\.?.*?box/i.test($this.val()) == true) {
                $("#button").attr("disabled", "disabled");
                $("#address").css("border", "2px solid red");
            } else {
                $("#button").removeAttr("disabled");
                $("#address").css("border", "2px inset");
            }
        };
    });
});