Replacing a string with another on button press

Replacing a string with another on button press

Apologies for lack of code but I'm really struggling to get started with this one.

This is the code I'm looking to manipulate I'm wanting to change the target when the appropriate button is pressed
  1. <embed type="application/x-vlc-plugin"
  2.          name="video2"
  3.          autoplay="yes" loop="no" hidden="no" width="100%" height="96%"
  4.  target="udp://@239.192.2.1:1234" />
So the buttons will have the following values attached so that when pressed they will replace the default target value in the code above (and hopefully change channel):

Button 1 (CITV) - "udp://@239.192.3.2:1234"
Button 2 (CBeebies) - "udp://@239.192.4.19:1234"
Buttom 3 - (CBBC) - "udp://@239.192.4.18:1234"

Thanks in advance
Andy