IFF Statement with multiple Conditions

 
//<%#IFF (Eval("SITEID").ToString() =="35" OR Eval("SITEID").ToString() == "18","<a href='/"+Eval("SeoName")+"/' ><strong>"+Eval("FRIENDLYNAME")+"</strong></a>", "")%>

Ok I will admit I have no Idea what I am doing, I am just trying to create a simple if statement with two conditions.

I know enough in .net to hurt myself but not enough to figure out how to create a simple statement.

Also if someone could explain what is the difference between iff and if!

Thanks