Do you know somethink about commands like that?

[Alexey?]

<!--[if gte IE 7]>

<![endif]-->

<!--[if !IE]><!-->

<!--<![endif]-->

Do you know something about those commands?
and do they Exist to FF or Opera?

[Dismounted]

No. They are special commands that only IE understand. They are used to add code to only IE (with an option of specifying an option). All other browsers interpret it as normal HTML comments (and thus, ignore it).

[Alexey?]

ok.
never mind you can lock the thread