Tutorial # 7 - How to display a gadget on a specific post or page OR on every post and page except a specific one

To display a gadget only on a specific post or page

Follow exactly the same approach as in Tutorial # 6 - How to make a gadget/widget appear only on the front, home, or landing page.

But instead of

<b:if cond='data:blog.url == data:blog.homepageUrl'>

in order to display a gadget only on a specific page, use this code, and put the address of the page or post instead of POST-URL:

<b:if cond='data:blog.url == "POST-URL"'>>

To display a gadget on every post and page except a specific one

Replace the double equals signs (==) with the HTML code for not, which is an exclamation mark followed by an equal sign (!=).   For example:

<b:if cond='data:blog.url != data:blog.homepageUrl'>