Coding Javascript

Where URLSearchParams fail

I’ve been working on a project, and one of the functions needs to get the parameters from the URL. Since IE compatibility wasn’t a requirement, I decided to use the URLSearchParams interface.

const urlParams = new URLSearchParams(;
if (urlParams.has('firstname') && urlParams.has('lastname') && urlParams.has('email') && urlParams.has('subs') && urlParams.has('unsubs')) {
const firstName = urlParams.get('firstname');
const lastName = urlParams.get('lastname');
const email = urlParams.get('email');
const subs = urlParams.get('subs');
const unsubs = urlParams.get('unsubs');

And this seemed to work fine, until I got to the testing phase.

Where it falls down is if you have special characters, like a ‘+’ in one of the parameters (like an email field). The value returned from the .get() method strips the special character out of the string and replaces it with a space. Frustrating.

So I had to abandon using the new hotness and fall back to using good old regex for getting the values.

getParameterByName(url, name) {
var results = new RegExp('[\?&]' + name + '=([^&#]*)').exec(url);
if (results==null) {
return null;
return decodeURI(results[1]) || 0;
// usage
getParameterByName(window.location.href, 'email')

If I did’t have to deal with email addresses that allow special characters, I would have loved to use URLSearchParams. The future is bright, but unfortunately it’s not perfect.

By Ted

Longtime web developer, part time photographer and musician. Born in the north, came of age in the south. Lover of open source web technologies and user/supporter of Wordpress.