.css('background-color',null) returns a String object

[sgbeal]

Hello!

The subject line says it all:

var v = $(foo).css('background-color',null); alert(v.toSource()); == (new String("transparent"))

!!!

i'm assuming that this is specific to background-color, and maybe other color-related CSS fields, but have not verified that.

The bug here is that the API docs say that the function returns a jQuery object, and here it returns a String object.

Using 1.1.3.1 packed.

[sgbeal]

It was explained to me on the list that the basic problem here is that css() assumes that a null/undefined as arguments[1] means that it should be invoked as a getter. A better solution for determine whether to call as a getter or setter is to use arguments.length instead of checking if arguments[1] is null/undefined. null is a valid value (at least for some fields) and undefined can easily be passed as a second argument by client-side code, e.g. css('foo',obj.missingAttributeHere).

[davidserduke]

I'm not aware of a case where undefined or null are valid css values. If someone can come up with such a case feel free to reopen the bug with the additional information.

This form of argument detection is common in jquery.