Javascript 24hr-time issue

I looked around for a 24hr JS time script and found the following from http://www.crays.com/jsc/jsC4Udate.htm:

Time in 24-hr format

<SCRIPT Language="JavaScript">
<!-- hide from old browsers
  var curDateTime = new Date()
  var curHour = curDateTime.getHours()
  var curMin = curDateTime.getMinutes()
  var curSec = curDateTime.getSeconds()
  var curTime = 
    ((curHour < 10) ? "0" : "") + curHour + ":" 
    + ((curMin < 10) ? "0" : "") + curMin + ":" 
    + ((curSec < 10) ? "0" : "") + curSec 
  document.write(curTime)
//-->
</SCRIPT>

Code (markup):

After testing it, I realised at 12pm the time goes to "00:00:00" instead of staying at 12. At 12am the time goes to "00:00:00" which is fine. How can I fix this or is there a better written script around?

 

Another questions is how to code the following;

If the time is between 7pm and 7am

do this​

else
If the time is between 7am and 7pm

do this​

 

Hi SuPrAiCeR69,
I hope this will work:

Martin