You don't need a manual to figure this out. As Peter is saying, you use the same method that you use to source a common style sheet on all your pages. You just use a
Note the source references in each of the listings. Most of my web pages are down several directory levels, but I keep all the scripts, except for the page specific ones, in a common area. All of the pages simply use relative links to access everything. This way I don't need multiple copies and can still keep my site neatened up. There are multiple "lib_?.js" files because they contain different groups of functions, and it's easier to keep them separate.