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?

Continue reading

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!)

Continue reading

Content Performance Policy: One More Step For Web Performance?

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