JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="metin" />

JavaScript

$("#metin").live("keyup", function () {
    var metin = $("#metin").val();
    if (metin.indexOf('%') >= 0) {
        var metin = $("#metin").val().replace("%", " ").toLowerCase();
        $("#metin").val(metin);
    }
});