JSFiddle - React, Tailwind, and code Playground

JavaScript

function checkUrlTest(url){
          
    // Try this
    var urlregex = new RegExp("^(?!www | www\.)[A-Za-z0-9_-]+\.+[A-Za-z0-9.\/%&=\?_:;-]+$")

            return urlregex.test(url);
        }
        url3 = "yahoo.com";
        url4 = "www.yahoo.com";

        alert('===> ' + checkUrlTest(url4) + '===> ' + checkUrlTest(url3));