HTML external flashVars... HELP

i found a website which makes mp3player for profiles on friendster and myspace. And it makes a code like this format

<embed flashVars="var1=hi&var2=hello" ...

i don’t really know the other tags, but the way it makes an swf file load a flashVar on the same html file that will also load flash. Can anyone help me on how this thing works. Or what acctionscript codes can call those flashVars?

I know how to handle txt file and xml file but not this way.