Wilzer, even if you try to paste this code to the desktop Custom text/HTML widget on our Demo page, you will see the same result - the code will disappear. This happens because the code is not correct. Custom text/HTML widget it's a module that is integrated into the page structure. The page itself already comes with <html>, <head>, <body> tags. So if you need to inset a link, you just need to paste:
<p><a href="
http://ytcspb.net/closeupsmobile/mobilesept2015.html">Mobile Closeups</a></p> code into this widget.
But if you are talking about new mobile custom page this code will work. See the screenshots:
But it's still not correct to use the code in full version.
It will be enough to paste <p><a href="
http://ytcspb.net/closeupsmobile/mobilesept2015.html">Mobile
Closeups</a></p> code.