Performance-wise: request JSON and render in JS, or request the entire HTML? [duplicate]

Answer 1

This was mentioned by Nicholas Zakas of Yahoo in his artical/talk at Velocity 2010,

it sounds like you're into javascript performance so it's well worth checking out the slides/pdfs.

includes stuff by Steve Sounders and a load of people i've never heard of:

http://en.oreilly.com/velocity2010

edit: if i rememer correctly the conclusion was html is usually better due to IEs slow json parsing (i think!)

Answer 2

Bear in mind that to the user, what actually matters is not the total time but what it looks like to them.

• Situation A) User presses a button, nothing happens for 2 secs, then data loads.
• Situation B) User presses a button, it says "please wait" or something, then data loads 3 seconds later.

To most users situation A will actually seem slower.

So whatever you do, really try to get progressive rendering working for you so the user sees something happening ASAP.

Answer 3

Probably no conclusive answer. But consider that although from a request perspective AJAX returning JSON is lighter than requesting the whole page with PHP. Processing the JSON request and updating the page components has a higher management burden.

Have you considered a hybrid? AJAX requests where PHP returns small chunks of HTML.

Answer 4

Depends on the type of site more than anything else imo.

• Do you need it to degrade gracefully?
• What browsers are your target audience likely to be using?
• What kind of connections might they have?
• How many hits will the site have?

It might, for example, be fair to assume that 'tech' site will be visited by people with faster computers using decent browsers with fast connections.

If you've got to support IE6 then i'd be wary of too much javascript, but its something that needs to be tested really.

I tend to render on the server generally, its just easier, but then again i make low load intranet sites generally!