Optimizely Render-blocking JavaScript

**theenergycell** · **theenergycell** 08-23-16

Hi there,

We are using the Magento Optimizely extension and Google PageSpeed Insights is reporting that the script is 'render-blocking javascript'.

Is there anything we can do here? The script seems to be added right after the opening <head> tag.

**robertchan** · **robertchan** 08-23-16

Verbatim from Google - "scripts that are not critical to initial render should be made asynchronous or deferred until after the first render." The only issue with something like a deferral is that you run the risk of page flashing. Strictly abiding by Google's recommendation may lead to unexpected issues in Optimizely's performance.

Robert Chan

**theenergycell** · **theenergycell** 08-24-16

Thanks @robertchan. I can modify the official magento extension to make it async, but will this affect our experiments on mobile?

It's currently affecting the site anyway as it is.

**robertchan** · **robertchan** 08-24-16

Anytime, and it should have the same effect as it does on desktop.

Robert Chan

Optimizely Render-blocking JavaScript

Optimizely Render-blocking JavaScript

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Re: Optimizely Render-blocking JavaScript

Re: Optimizely Render-blocking JavaScript