Document in Document Scripts

[Donomegax]

I know that there is a script for Document in Document and I've learned how to use it. However, I am a bit confused of the actual structure. I am going to give an example so that who ever reads this will understand.

Example of original document.
Function I want done: I would like to change the letter E to the letter J
Doc.htm
ABC
DEF
GHI

Document after function
Doc.htm
ABC
DJF
GHI

Document the letter J is drawn from
Doc2.htm
JKL
MNO
PQR

Is this possible? Or does Doc2.htm have to look like this;
In order for this to work?
Doc2.htm
ABC
DJF
GHI

Please help?

The actual website I am talking about is www.silverstatetour.com . The issue is with the calendar as well as the middle bar and the content I would like it to change too. I am also having an issue with the calendar and was wondering if their is an easier way to make it functional?