JSFiddle - React, Tailwind, and code Playground

JavaScript

var url = 'http://www.google.com/';
var url2 = 'http://www.google.com/dfdf';

function UrlExists(url) {
    var http = new XMLHttpRequest();
    http.open('HEAD', url, false);
    http.send();
    return http.status != 404;
}
console.log(UrlExists(url));
console.log(UrlExists(url2));