Need explanation of XPath syntax

Question

Can anyone explain the XPath syntax written below:

xmlDoc.documentElement.selectNodes("//*/Expression[.!='']")

Basically, I need clarification of the argument path of the above syntax.

Answer 1

Select all the <Expression> elements which:

1. are not root elements
2. and have non-empty value

//*/ - this means any but root

Expression - element name

[.!=''] - this means current node value is not empty, i.e. current node . is not != empty ''