Check if your web server supports "server-side includes" ("SSI"). If it does, there's no need to use anything other than straight HTML and CSS. No scripting languages needed.
I use this on my website to put the top banner, main menu, and sidebar into their own files. Then, on each page, I simply include this at the top of the "body" section:
I then have a "inc" directory within my "htdocs" directory (some systems use "public_html" instead), where I place these files.
Over the holidays, I had this in my "/inc/banner.inc" file:
Please note that our offices will be closed for the holidays from
Thursday, 24-Dec-2009 through Sunday, 3-Jan-2010
This notice then "magically" appeared in the banner on every page on my site.
In my CSS file, I have this style for my sidebar, to keep it on the left side:
#SideBar {
background: rgb(162,192,198);
color: black;
font: 10pt Arial;
width: 15em;
float: left;
/* padding: 5px 10px 5px 0px; */
margin: 0px 2em 0px 0px;
}
and within "inc/sidebar.inc", I place everything within