JSFiddle - React, Tailwind, and code Playground

JavaScript

var str = "www.example.com/index.php?a=1&b=2&c=3";
    var newStr = str.substring(str.indexOf("?") + 1);
    var myStringArray = newStr.split("&");
    
    var arrayLength = myStringArray.length;
    for (var i = 0; i < arrayLength; i++) {
      myStringArray = myStringArray[i].substring(0, myStringArray[i].indexOf('='));
      alert(myStringArray[i]);
    }