Nicholas Zakas,Staff Software Engineer at Box, discussed web, mobile, and app performance and JavaScript trends with theCUBE co-host John Furrier and Dave Vellante, live at the O’Reilly Velocity conference.

Commenting on Velocity, Zakas said there was “so much cross-conversation going on, people sharing ideas and experiences.” Identifying the main conversation points, he mentioned “a lot to do with the amount of JavaScript people are using and the JavaScript solutions they are using,” discussion about mobile performance, something that was still really new but being dealt with as a “fresh problem”, as well as the challenges of swithcing to 3E for mobile.

Everything starts with analytics

Asked about the perception of speed in user experience, Zakas pointed out that “perception is more important than reality, if you make people believe what they’re seeing is faster than it is, they’re happy.”

“Everything starts with analytics,” Zakas said “it’s hard to know if you’re slow or not unless you’re watching” the metrics. “Getting to a good definition of what is fast vs. what is slow is the first step,” then companies need to figure out the right analytics and metrics. If the time spend on a server rendering a page is of 2-3 seconds, “you should be unhappy.” After that, you have to test it on users and see their reactions and get feedback.

“There’s a lot of things to do with perception,” Zakas expalined. “If you have a large blank space on your page and people stare at that, it looks slow.” If frames or a loading bar are added, the perception changes.

Asked about the current starndard app and monitoring analytics, Zakas said that there were different tools but they all did the same things. In the case of web apps, what is usually measured is unload time – how long it takes till everything on the page is completely loaded so people can use the app. He mentioned Boomerang, a tool that measures unload time, but also other associated times: how long a DNS look up take, how long it takes to get data to the client, JavaScrip and images loading times, etc.

“The most interesting part is that you can write one language and build a complete stack out of it. Developers love JavaScript but were not enamored with the browser side of it,” Zakas explained. “On the server, you control that environment completely. Now, there’s actually opportunity to have a really awesome, fulfilling job by having NODE on the server. When you have node compiling JavaScript, it can run just as fast or faster than Java and PHP.”

“The most imp thing is to understand your users,” Zakas said. “Why are they coming to you and what are they trying to do,” and make sure you enable them to do it, provide the right experience. “After that, you’re free to do pretty much whatever you want. If there is some way to progressively load things, so that you don’t get large blank spaces,” the app will seem faster and it will improve customer experience.

The thing with Javascript…

Talking about his presentation at Velocity, Zakas stated “I love JavaScript, it’s my favorite language. The big issue is that people are using so much of it that they run into problems they wouldn’t otherwise run into.” Based on his experiences with clients, people have 1-2 MB of JavaScript loaded into the browser, which slows everything done. Upon analyzing the code, he noticed that on average, about 35-40 percent of that code would be used when the page is completely loaded. The mentality is “computers, browsers are faster, I’m going to load a lot of code.” Developers expect computers to catch up and tend to load a lot of code. “You can achieve a lot with less code if you actually think about what you want to do with it,” Zakas explained.

“One of the biggest things is to make sure you take advantage of the various layers of your applications,” Zakas advised, referring to JavaScript, CSS, HTML, browser, and server. “When you are able to delegate responsibilities efficiently, things always work better. You create a nice balanced web app where you don’t touch JavaScript every time you want to make a change.”