XML Schemas

Hey world,

I've got a Schema question for you that has been taxing me for while.


If I have a xml document that looks like

<?xsl version="1.0"?>
<content>
     <element type="one">
           <file>This is only allowed if the element has @type equal
to one</file>
    </element>
    <element type="two">
           <text>This element is only allowed if the element has @type
= 'two'</text>
    </element>
</content>

Is it possible to put this restriction like this on with a schema? I
have looked around for any kind of a hint at a solution but have
gotten nowhere!

Is it even possible to put restrictions based on attributes?

Now I know I can just use a different element but what would i do if i
was writing this schema to valid a section of xhtml where you can have
<input type="submit"/> and <input type="file"/> which have complety
different requirements?


Thanks in adavance for any help you can give me :)
Richard