Plugin-tjekker

Jeg har selv svaret:

"Unfortunately, this task [plugin tjek] only works in certain browsers. Internet Explorer 4 (all platforms) includes the plugins object, but it's always empty. [...] Thankfully, though, Netscape browsers (since version 3) and [IE for Mac...] allow access to checking plug-ins via JavaScript." (Negrino and Smith, _JavaScript for the World Wide Web_, 4th ed., 27).

Så det var altså ikke document.write delen der var gal. I NS6 var jeg bare kommet til at disable JS :-\

Så derfor skriver IE: "You haven't Adobe Acrobat [osv.]" og NS: "You have Adobe Acrobat [osv.]". Ikke smart.