Show template content at runtime when a value in the runtime Data Source has been populated. For example:
<core:optional for="IsLoggedIn"> <p><a href='logout.php'>log out</a></p> </core:optional> <core:default for="IsLoggedIn"> <p><a href='login.php'>log in</a></p> </core:default>
The for attribute is used to identify the name of the variable in the dataspace.
This tag is often used in conjunction with the <core:default> tag for simple if/else logic.
Please have a look at the examples section to see this tag in action.