Which JavaScript property names can be unquoted? When can dot notation be used?

http://mathiasbynens.be/notes/javascript-properties

by mathias • 14 years ago

13 6 14 years ago

mathiasbynens.be

gf3• 14 years ago

Informative 𝘢𝘯𝘥 how!

mathias3• 14 years ago

http://mothereff.in/js-properties#%F0%9D%98%A2%F0%9D%98%AF%F... :(

simcop23872• 14 years ago

One thing that you might want to keep in mind is that I seem to recall IE 6/7 being funny with quoting here compared to other browsers. Firefox and Chrome behaved like this but earlier IE's I always ran into problems with if I didn't quote everything.

mathias3• 14 years ago

The ECMAScript spec states that engines are free to choose which Unicode version they support, and that Unicode 3.0 is considered to be the lowest common denominator.

Old IEs use an outdated Unicode version (I’d guess Unicode 3.0) to determine whether a given string is a valid identifier name. When using the Unicode 6.1.0 database, much more identifier names are allowed. (More on that here: http://mathiasbynens.be/notes/javascript-identifiers & http://mothereff.in/js-variables.)

Could that be what you’re referring to? Can you give a concrete example of a property name that should be allowed, but fails to work in old IE?

simcop23872• 14 years ago

Possbily, I'll try to dig up something from my old projects. I wouldn't be surprised if I seem to be misinformed about it a little.

Which JavaScript property names can be unquoted? When can dot notation be used?

Related Stories