Example 2     <<      >>       intro       contents     

An element type has element content when elements of that type must contain only child elements (no character data), optionally separated by white space.

  DTD   HOME     

The root element XXX must contain precisely one element AAA followed by one element BBB. Elements AAA and BBB can contain some text but no other elements:

               <!ELEMENT XXX (AAA , BBB)>
               <!ELEMENT AAA (#PCDATA)>
               <!ELEMENT BBB (#PCDATA)>
               
            


  Valid documents   HOME     

A valid document containing some text:

               <!DOCTYPE tutorial SYSTEM "tutorial.dtd">

               <XXX>
               <AAA>Start</AAA>
               <BBB>End</BBB>
               </XXX>
               
            

This document is also valid:

               <!DOCTYPE tutorial SYSTEM "tutorial.dtd">

               <XXX> <AAA/> <BBB/> </XXX>
               
            

  Documents with errors   HOME     

Element BBB is missing:

               <!DOCTYPE tutorial SYSTEM "tutorial.dtd">

               <XXX> <AAA/> ___ </XXX>
               
            

Element BBB must follow element AAA:

               <!DOCTYPE tutorial SYSTEM "tutorial.dtd">

               <XXX> <BBB/> <AAA/> </XXX>
               
            

Root element XXX can contain only one element BBB:

               <!DOCTYPE tutorial SYSTEM "tutorial.dtd">

               <XXX> <AAA/> <BBB/> <BBB/>  </XXX>
               
            

Root element XXX must not contain any text.:

               <!DOCTYPE tutorial SYSTEM "tutorial.dtd">

               <XXX> Elements: <AAA/> <BBB/>   </XXX>