How can I display the page number of a cross-referenced object, but only if the object is on different page?

I am creating a command called fullref{<label>} that takes a label and outputs the number of the labeled object and name and optionally the page number where to find the object if it’s on a page that differs from where the cross-referencing call-out occurs.

Examples:

Let a label label{chap_intro} and a text … as seen in chapter fullref{chap_intro}..

If they are on the same page, the text will output:

… as seen in chapter 1.1: "Introduction".

If they are on different pages, the text will output:

… as seen in chapter 1.1: "Introduction" on page 2.

Here is my command so far:

latex

newcommand{fullref}[1]{ref{#1}: "nameref{#1}" ifthenelse{
  equal{thepage}{pageref{#1}} % if the current page and the referenced page are the same
 }
 {} % then do nothing
 { on page pageref{#1}} % else append "on page …" if different
}

Even when on the same page, it displays "on page …".

What did I do wrong?