From a preference standpoint, I don't really care either way. This comes more from the construct that single quotes are string literals and double quotes are interpreted strings. In dynamic languages, there can often be a performance hit due to the parser having to attempt to look for something to parse in the interpreted string. In PHP, this hit could sometimes be pretty big. In Ruby (at least when I researched this a few years ago, the hit was minimal). JavaScript is interpreted within the browser and will vary in performance, so generally speaking it's probably a good habit to just use single quotes unless you need double. It's not something that is worth going back and changing in hundreds of files, but if done up front, I think it's ideal. Thoughts?