Automatic hiding of unused content area...

When you have a site layout which is 3 columns on the frontpage and 2/3 columns on the subpages, you could create two datastructures.

The problem is that it is not very intuitive for the user to change from 2 to 3 columns on a subpage, as he has to both change a datastructure and the template.

So instead of going for two datastructures, I have managed to hide the 3rd column if it is empty.
So the thing that decides if the 3rd column is shown, is if I have put any content in it.

This is the typoscript in the datastructure on the field/area which I want to hide if it is empty:
    <TypoScript><![CDATA[
    10= RECORDS
    10.source.current=1
    10.tables = tt_content
    10.stdWrap.ifEmpty{
        cObject = LOAD_REGISTER
        cObject.rightContentEmpty = 1
    }
    10.stdWrap {
        required = 1
        wrap = <!--TYPO3SEARCH_begin--> | <!--TYPO3SEARCH_end-->
    }
    ]]></TypoScript>
So here I say that if there is no content the register should add rightContentEmpty with a value of 1.
 
In my typoscript template (setup field), I add the following code:
page.headerData.1001 = TEXT
page.headerData.1001 {
  value (
  <style type="text/css">
  /*<![CDATA[*/
  #right {display:none;} #normal {width: 501px; margin-right: 33px;}
  /*]]>*/
  </style>
  )
  if.isTrue.data = register:rightContentEmpty
}
So if rightContentEmpty is true, then the css will be added with the headerData.