why doesn't the following script work?

Code:
<script language="JavaScript">
 <!--

self.moveTo(("0"),("0"))
self.resizeTo("800","770")
void(outerWidth=800);  
void(outerHeight=770);
self.menubar.visible=false;
self.toolbar.visible=false;
self.locationbar.visible=false;
self.personalbar.visible=false;
self.scrolling.visible=false;
self.statusbar.visible=false;

//-->
</script>
the error = self.menubar is not an object