How to add  in drupal?
You really shouldn't be putting things like that in a drupal block via the UI anyway because someone with permissions could come along and mess it up and then everything breaks.

You can add/remove/change markup on the page by editing the templates in your theme.

For example you could add your template script tag into the page.tpl.php file of your theme.

Assuming you are using the same template on all pages (or a bunch of pages) or you just want a template on a specific page then this is really straight forward.

If you have more complex requirements you might need a large amount of template overrides or you may want to use some code in template preprocess functions in template.php to make things simpler.

For more information on this see Theming Drupal 6 and 7. There is a lot of info in there.