Performance Audit 2017: New Loader Snippet without IFRAME

[nicjansma]

The Boomerang Loader Snippet has a cost, more than a regular <script> tag would. Here's a breakdown on machines I've tested:

We should investigate alternative ways of loading Boomerang in an asynchronous, non-blocking manner.

@bluesmoon and others have been investigating this.

[yoavweiss]

A preload-based snippet could look something like: http://jsbin.com/sobacusizu/1/edit?html,console,output

[nicjansma]

After extensive research and testing, we're released a significant update to the mPulse Loader Snippet that addresses a lot of the performance concerns and several SEO concerns with the previous snippet. Going forward, we are recommending use of the new "Version 12" of the mPulse Loader Snippet, documented here: https://akamai.github.io/boomerang/tutorial-loader-snippet.html

Version 12 is now CSP-compliant and avoids IFRAMEs most modern browsers.

This snippet avoids creating an IFRAME in any browser that supports Preload.

This change is in 33371c3