INCORRECT U LOSE

JavaScript

function updateQueryStringParameter(uri, key, value) {
  var re = new RegExp("([?|&])" + key + "=.*?(&|$)", "i");
  separator = uri.indexOf('?') !== -1 ? "&" : "?";
  if (uri.match(re)) {
    return uri.replace(re, '$1' + key + "=" + value + '$2');
  }
  else {
    return uri + separator + key + "=" + value;
  }
}

var uri = "http://example.com/Test.html#HashValue";
uri = updateQueryStringParameter(uri, "QueryKey", "QueryValue");

document.write(uri);