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Analytics with vanilla JS: page views

Ziga Brencic on November 29, 2019

How to get basic page view statistics? Second article in the series Analytics with Vanilla JS. Motivation here. Today we'll look into the impelen... [Read Full]
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That's an interesting exercise, looking forward to the next posts.

I think what's essential is not amount of data, but just the necessary and right datapoints that answer the right questions. I feel Google Analytics is bloated, difficult to use, it's like "Microsoft Office" of web analytics. We only need a text editor with markdown.

I'd focus more on which data and how to present, instead of too much on collecting everything possible...


Hey 👋 couldn’t agree more one the analogy you made. Might use it in the future 😉

Speaking of simplicity. What would you focus on collecting and visualizing? I have few things in mind but I’m open to suggestions where to take the above series 🙂 Let me now.


In my (relatively short) experience:

It doesn't hurt to have aggregate metrics like time series of sessions, pageviews, geographical distribution of users, etc. I think what's challenging is making it easier (in the UI) to draw answers to simple questions:

  • In what countries is the site most popular, which topics are more interesting to each country?
  • Which source brings the best traffic (perhaps people that spent more time on the site, on average)?

But the bottom line is: almost always we want people to take certain "actions" - subscribe to newsletter, buy stuff, start a Trial account, etc.

What I think people really need is to connect sources and efforts to actions.

An "effort" is: "I publish an article about a service I think is valuable to other devs". Or "I post on social media about a new feature or a case study of this service".

A source could be DEVto, in case of article, or Twitter in case of the post.

Even if the person comes in today, but only take the "action" 3 weeks later, I would like to know which "efforts" contributed. There are automation marketing platforms that would give that, but (again) they are so bloated that you need "marketing specialists" to configure them correctly. Not to mention how expensive they are. It's ridiculous, should be really simple and cheap for individuals, SMEs and startups.

Side note: it's become common sense for developers to demonize marketing; although I understand there are unacceptable abuses nowadays, I find amazing to see the rationale of someone who takes a 6-figure salary from a company (which in some cases is the largest privacy abusers) that must connect to a market that can benefit from its service (a.k.a. Marketing) in order to keep money flowing in to pay for fat salaries every month. And then this person despise who works in marketing, analytics, etc. It's amazing...

Hey thanks for this.

As I mentioned in the first article of the series Motivation I'm going towards analytics that can be integrated directly into product development cycle. What you described definitely fits the bill. Really good point if you don't mind I'll use it :)

On marketing <=> developer relationships I couldn't agree more. Software is useless if nobody's using it and developers are too often way to far from direct customer interaction.

If you ask me. Software development is easy. Selling the product is hard :D

Sure, feel free to use the ideas! Glad I could add something positive to the discussion! Please, keep us posted as you move forward 😉

I couldn't agree more: software is not an obstacle, being able to sell profitably and grow healthy is really hard!

Great. I want to bounce another thought.

Tracking sources of traffic is easy. Proper URL parameters and that's it. But connecting efforts to actions over multiple web page user visits that's a bit harder.

I've come up with a solution that uses localStorage but local storage can disabled. Sure the amount of users with disabled localStorage will be small but still.

Is there maybe a more elegant way to connect multiple separate web page visits to a single user? I'm probably missing something due to my basic knowledge of JS.

I would suggest generating a unique hash for each visitor. Maybe an MD5 hash of multiple values concatenated:

  • User-agent
  • IP address
  • Timestamp
  • Random 9-digit number (extra careful avoiding hash collision)

Store this hash as a cookie in the browser. When the person comes back later, your script can identify it's the same person.

Store the user hash with every interaction (even pageviews). Later, when you're analyzing an action (e.g. "user subscribed to the service"), you can get the user-hash and search every other interaction associated with it in the past.

About tracking the source of traffic, it's not going to be easy anymore. All major browsers are adopting strict "no-referrer" policies now. What this means is:

  1. The person is reading an article in
  2. There's a link to your site (, in which the reader clicks
  3. When requesting your site content, the browser will send only "" in the Referrer Header, not the entire URL

They're making this switch for privacy and security reasons. It's a good thing, but it will make it a lot more difficult to track sources with precision. Unless we use UTM parameters in the URL, there's no way to know from which page the visitor came.

Hash thats clever 🙂 I was thinking about just some unique user id. Thanks.

On URL. Privacy reasons I get and I know that UTMs are more reliable but what are the security issues of referrals?

It's possible for the origin to add user sensitive data in the URL. It's bad practice, but I'd say there's 99.99999% chance that at least a handful of sites is doing that right now.

In that event, the target site can access user data without its consent from the referrer header.

Alright yeah that’s problematic. Never thought of that 🤷‍♂️

Me neither!.. 😊

I was just pissed at Google Analytics recently and thinking about building something better and started researching, your article caught my attention 😄

Haha nice :D

My disagreement with Google Analytics got on this path to yeah. What encouraged me to start building my own analytics were those guys:

Before that I never thought that one could build reliable custom analytics. But apparently two developers did.


As an improvement, have a look at the Fetch API and Beacon API 🙂


Thanks for pointing that out.

I didn't know about Fetch and Beacon API. Though after a quick google search I noticed that they are not supported in IE. At least according to

Any thoughts how to perform asynchronous requests in IE?

It would be a performance improvement indeed.


I would recommend not supporting IE anymore, unless absolutely needed. You can always fall back to XHR if fetch is not available (polyfill).

IE is still supported and developed right? What am I missing here?

I checked my personal page and yes percentage of IE users is low but still. Fall back to XHR sounds like a good option.

How would you do the fall back? With try and catch? Or would you try to detect if user is on IE? If yes how? As far as I know there's no consistent way to check browser version.

As I mentioned in the article I'm a bit light on JS since I come from data science. So any tips are welcome :)

IE 11 is still supported by Microsoft, but not for long. Adding a development focus on IE in 2019 is a waste of efforts, unless it's absolutely necessary. You can do it in a progressive way, where a site is usable on IE, but won't support all the features.

Falling back to XHR can be as simple as checking if (!window.fetch).

There used to be some specific HTML comments for detecting if browser is IE (not supported in IE 11). But feature detection is a better alternative than browser detection.

Alright didn't know that. Feature detection there is then.

Thanks again.


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