eHlpDhtm.js edition

I personally don't recommend adding anything to that file as I'm pretty sure it will be overwritten when you install an update. I don't even know if that file exists in the New UI version of RH.

If you are writing completely new scripts, I would recommend including them in a different way as one or more standalone script files.

If you are already using a master page in your project, you can add a reference to your custom script files in a master page. Click the Edit Header button, which will put the proprietary header section in focus (or add it if required). Any scripts added will then be applied to every htm file in the project.

If you're not using a master page, I recommend adding one. Add your link to the script in the proprietary header section. Then in your output SSL, tick Apply to all Topics, then select your master page. (Note: if you already have a stylesheet selected here, apply the stylesheet to your master page instead, so it will still apply to all your topics.)

Well, in my copy of RH11, it's sitting in C:\Program Files (x86)\Adobe\Adobe RoboHelp 11\RoboHTML\

Two approaches to this - edit the file(s) post-generated and save off a copy to be copied back into the output after the next round of output creation; or, find the "factory" copy of the files, make a backup of the original file and then edit them in their source location. Make sure you keep a copy of your edited files to preserve them in case a future update wipes the factory location. Personally, I use the first approach - so much simplier.