Javascript source missing in the page at first loading

I have an Html page executed in an Iframe where at first loading, sometimes in the source I see that js code is missing at all including the opening js script tag: <script language="Javascript>" but more surprisingly (at least to me), I have links like: href="javascript:namefunction where the string javascript:namefunction is missing too. Is this javascript:namefunction missing part connected to the wrong js loading in the page?
I tried to understand the possible reasons but could not figure out.