OK, I thought it might be good to make this work for 3.7 as well (because it didn't).
Here is how to do it:
In the template 'memberinfo_block_contactinfo'
FIND THIS CODE:
PHP Code:
<a href="$prepared[homepage]" target="_blank">$prepared[homepage]</a>
REPLACE WITH:
PHP Code:
<!-- Pop-Up Warning Before Visiting Member's Homepage by 713JunctionP -->
<a href="$prepared[homepage]" onClick="return confirm('The link you are trying to access may not be a part of the $vboptions[bbtitle] network. Click OK if you wish to trust this member and visit their website anyway. Otherwise, click CANCEL to halt visitng this members website.')" target="_blank" dir="ltr">$prepared[homepage]</a>
<!-- / Pop-Up Warning Before Visiting Member's Homepage by 713JunctionP -->
Great Mod BTW 713JunctionP,