When to prefer JSON over XML?

Question

My requirement is just to display a set of values retrieved from database on a spread. I am using jquery.

Answer 1

From the first line at http://json.org/xml.html

Extensible Markup Language (XML) is a text format derived from Standard Generalized Markup Language (SGML). Compared to SGML, XML is simple. HyperText Markup Language (HTML), by comparison, is even simpler. Even so, a good reference book on HTML is an inch thick. This is because the formatting and structuring of documents is a complicated business. . . .

Clearly JSON is faster, but it's even more clear that it is hard to read. Use JSON for speed, use XML if there will be human-interaction and you can sacrifice the speed.