It doesn't seem to support all attribute selector contents

[fregante]

I'm looking to use these types in my querySelector wrapper module but in my tests it seems that the + character is not supported in attributes:

'link[type="application/json"]' => HTMLLinkElement
'link[type="application/atom+xml"]' => Element

I wonder what other characters can create problems

[g-plane]

The reason is + is a selector combinator, then it treats xml"] as unparsed string.

[fregante]

Should it be escaped? When quoted, the selector works