The best solution is to include it in the (sub)theme's .info file. Next best is to include it in the .info file of a custom module, if you have one. If nothing else works, there is hook_init(). Never, ever, hack core.

Nancy

Injustice anywhere is a threat to justice everywhere. -- Dr. Martin L. King, Jr.

From: Dotan Cohen

I need to add a Javascript include on all pages. I have grepped about
for "DOCTYPE html PUBLIC" but none of the files in
~/sites/all/themes/traction/ contains that text. The only other place
that seemed likely was ~/modules/system/html.tpl.php but adding the
Javascript include there did not make it appear in the page source.
Which file contains the <head> section HTML that is included in all
pages?