Output CONTROL is used to control how to display Xform data:

For example:

See an instance of XML document:

<instance>
<person>
<NAME>
<firstname>xxx</firstname>
<middlename>yyy</middlename>
<lastname>zzz</lastname>
</name>
</person>
</instance>

We can perform output control on above XML instance:

<p>First Name: <output REF="name/firstname" /></p>
<p>Middle Name: <output ref="name/middlename" /></p>
<p>Last Name: <output ref="name/lastname" /></p>
Output:
Firse Name:xxx
Middle Name: yyy
Last Name: zzz

Output control is used to control how to display Xform data:

For example:

See an instance of XML document:

<instance>
<person>
<name>
<firstname>xxx</firstname>
<middlename>yyy</middlename>
<lastname>zzz</lastname>
</name>
</person>
</instance>

We can perform output control on above XML instance:

<p>First Name: <output ref="name/firstname" /></p>
<p>Middle Name: <output ref="name/middlename" /></p>
<p>Last Name: <output ref="name/lastname" /></p>
Output:
Firse Name:xxx
Middle Name: yyy
Last Name: zzz