JSFiddle - React, Tailwind, and code Playground

JavaScript

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

alert(getParameterByName("param1","www.example.com/test?param1=1&param2=2"));