XPath: How to select nodes which have no attributes?

To address Marek Czaplicki's comment and expand the answer

//node[not(@*) or not(string-length(@*))]

....will select all node elements with zero attributes OR which have attributes that are all empty. If it was just a particular attribute you are interested in, rather than all of them, then you could use

//node[not(@attribute1) or not(string-length(@attribute1))]

...and this would select all node elements that either don't have an attribute called attribute1 OR which have an attribute1 attribute that is empty.

That is, the following elements would be picked out by either of these xpath expressions

<nodes>
    <node attribute1="aaaa"></node>
    <node attribute1=""></node> <!--This one -->
    <node attribute1="bbbb"></node>
    <node></node> <!--...and this one -->
</nodes>

See jsfiddle example here

//node[not(@*)]

That's the XPath to select all nodes named "node" in the document without any attributes.

//node[count(@*)=0]

Will select all <node> with zero attributes