Example of conditional blocks
this TBS template is W3C compliant 
Conditional Blocks enable you to display or hide an area according to a condition.
| Hello, You have selected the block #1.[onload_1;block=tr;when [var.blk_id]=1] |
| Good, it's now the block #2 which is displayed.[onload_1;block=tr;when [var.blk_id]=2] |
| Well, finally Conditional Blocks are very easy.[onload_1;block=tr;when [var.blk_id]=3] |
| This block is displayed by default.[onload_1;block=tr;default] |