using XPath how to select elements with absent attribute

Question

I would like to select all elements that have certain attribute or don't have it at all:

//job[@salary<"100" or !@salary]

This code is not valid. Which one is? Thanks!

Answer 1

//job[count(@salary) = 0]

I think :)

Answer 2

//job[@salary<"100" or not(@salary)] 

There isn't a not operator in xpath. See http://www.w3schools.com/xpath/xpath_operators.asp

Answer 3

//job[@salary<"100" or count(@salary)=0]

Tested it here and works fine.