html question!

[KAMiKAZE]

lol fileforums seem to use meta-tags which i'm looking for:
<meta http-equiv="Pragma" content="no-cache">
<meta http-equiv="no-cache">
<meta http-equiv="Expires" content="-1">
<meta http-equiv="Cache-Control" content="no-cache">

second and last 1 are unknown to me and i really don't understand the sence of these tags
found some interesting info on a PAGE , too!

@EMPiRE: i know you don't coded the forum, but probably you know the code of your forums can u help me out with the tags and the way they work?!

@Luciel: are u interested in html and java, too?? (if so do you have a own website or want to create one?)