All PhpED manuals, including php, javascript, css, html and all the other manuals can be easily updated or new ones can be added if necessary.
Tools->Settings->Help is the page that lists all currently attached manuals. In order to add new, please follow steps below:
-download chm file
-make sure it is not blocked otherwise you'll see Page not found or just empty page.
-open Tools->Settings->Help, click Add and select the file

To unblock CHM file please right click on it in Windows Explorer and select properties. If [Unblock] button is shown, please press it. For further info about blocked CHM files please read Microsoft arcticles:
http://support.microsoft.com/kb/902225/
http://support.microsoft.com/default.aspx?scid=kb;en-us;896358
http://support.microsoft.com/?kbid=896054
http://support.microsoft.com/default.aspx?scid=kb;en-us;892675