JSFiddle - React, Tailwind, and code Playground

HTML

<input type="button" value="go" onclick="dofunc();">

JavaScript

$.fn.gotof = function() {
    alert("I am calling form jquery");
};

$(document).ready(function() {
    alert("function is ready to use now");
});

function dofunc() {
    $.fn.gotof();
    $('input').gotof();
}