Ex-Googler reveals study and, yes, we’re lookin‘ at you, WordAds
If the web seems slow, blame third-party advertising and analytics scripts.
Many internet users have already come to that conclusion but Patrick Hulce, founder of Dallas, Texas-based Eris Ventures and a former Google engineer, has assembled data that clarifies the impact of third-party scripts in the hope it prompts more efficient coding.
Hulce has compiled a list of the third-party scripts residing in the top million websites and found that the 100 most common bits of JavaScript eat up about 59 per cent of script execution time.
„Third party script execution is the majority chunk of the web today, and it’s important to make informed choices,“ he says in the GitHub post where he presents the data.
Hulce during his time at Google worked on Lighthouse, a developer tool for browser performance profiling. It’s available in Chrome, from a command line app, or as Node.js modules.
Third party scripts represent only one factor that comes into play when calculating total web page load time. Network latency, bandwidth, file sizes and device processing power all come into play. But the time it takes to execute JavaScript code can have a significant impact too.
In an email to The Register Hulce explained that there are different types of user-perceived delay. „Visual delay, when nothing shows up or things are obviously still loading slowly, tends to still be dominated by network latency and large resource payloads,“ he said. „Large script files can contribute here, but execution time isn’t always the biggest culprit.“
At the same time, delays affecting interactivity, he said, like when users try to click on an icon and nothing happens immediately, are almost exclusively the results of JavaScript execution.
