JSFiddle - React, Tailwind, and code Playground

JavaScript

function getParameterByName(name,url) {
    name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]");
    var regex = new RegExp("[\\?&]" + name + "=([^&#]*)"),
        results = regex.exec(url);
    return results == null ? "" : decodeURIComponent(results[1].replace(/\+/g, " "));
}

var one = '/news/local/edit?user=marcus&owner=ffff';
var two = '/news/other/edit?user=josh&owner=ddd';
var three = '/news/local/edit?user=john';
var four = '/news/local/test/marcus/edit?user=ady&owner=aaaa';

alert(getParameterByName("user",one));
alert(getParameterByName("user",two));
alert(getParameterByName("user",three));
alert(getParameterByName("user",four));