jQuery attribute selectors: How to query for an attribute with a custom namespace

Question

Suppose I have a simple XHTML document that uses a custom namespace for attributes:

Answer 1

the syntax for matching by attribute is:

$("div[customattr=bla]") matches div customattr="bla"

$("[customattr]") matches all tags with the attribute "customattr"

with namespace attributes like 'custom:attr' its not working

Here you can find a good overview.