All posts by Damien Jubeau

Why you should avoid using document.write, specifically for scripts injection

Web performance testing tools like Google Page Speed or Dareboost already pointed it: injecting a script by using document.write instruction causes severe issues about websites loading time. Let’s talk about this topic one more time, as the next Chrome update to come won’t allow such scripts injections any longer. What kind of issues may you experience? Which alternatives to find?

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HTTPs is a requirement for your website

About a year ago, I have published an article about HTTPs usage growth: Chrome, Firefox and Google Search: HTTPS forcing its way. In this article I detailed some major announcements, that would probably result in pushing HTTPs forward.  

Ever since, requests using HTTPs reach 25% according to HttpArchive data (compared to 15% in April 2015).

In this post, we’re going to focus on today’s results of the previous announcements, on the last changes, and especially on why you should consider HTTPs as a requirement for your website (not only for security or SEO considerations!)

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Content Performance Policy: an alternative to Google AMP?

It’s not usual on this blog, but today I’m going to write about a proposal that might become real, but that is still at its very early stage.

It is now more than a year since we added a recommendation about Content Security Policy with our website analysis on It’s a great feature to add more security to your website, particularly to prevent your visitors from the effects of an XSS attack.   

The idea behind CSP is to allow website owners to offer a security policy that will next be applied by the web browser. For instance, it allows to whitelist explicitly some JavaScript files, or to ensure the use of HTTPs to request each resource within the page.  

Tim Kaldec and Yoav Weiss borrowed the CSP general concept to apply it to web performance topic, proposing a new HTTP header (Content Performance Policy), allowing to declare precisely the compliance level of a given page with some web performance best practices. Then, the user agent would be responsible to ensure the effectiveness of the announced best practices.   Continue reading

Website Speed Test, Dareboost tips for reliable results

If you’re reading this blog, you probably know that load time matters when it comes to user experience, a lot. And it’s even a major factor determining the success of a website.  

Server response time, speedindex or start render, or again fully loaded time, whatever is the metric you want to collect, your measurement method should take into account several major parameters if you want reliable results through time. Continue reading

Compare the speed and rendering of 2 pages

More and more of you were asking for it, so we did it :)
Comparison Tests are now available!

  • Would you like to know how your website is doing compared to a competitor, whether it is a challenger or the leader of your market?
  • Would you like to valorize your optimization work by comparing the new version and the old one of your client’s website?
  • Would you like to compare the speed of the mobile and desktop versions of your responsive website?

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