I want to be able to hook into the output buffer flow and add some conditional content to my WP pages.

What I want to do is test cookies and display a semi-transparent screen with a content box based on a cookies' condition.

I know how to construct the html and css to make this happen. I know how write the php to test cookies.

What I don't know is what add_filter() or what add_action() to use to make this hook in my functions.php file.

Can anyone provide direction or point me to the codex? I am just not sure what search arguments to use when I look at the codex.

Thanks

I want to be able to hook into the output buffer flow and add some conditional content to my WP pages.

What I want to do is test cookies and display a semi-transparent screen with a content box based on a cookies' condition.

I know how to construct the html and css to make this happen. I know how write the php to test cookies.

What I don't know is what add_filter() or what add_action() to use to make this hook in my functions.php file.

Can anyone provide direction or point me to the codex? I am just not sure what search arguments to use when I look at the codex.

Thanks

AMENDED

Here is what I want to accomplish:

I want the following to be added to each and every page on my site, regardless whether the page exists today. If I add a new page in the future, I want this to appear as well. (I wil handle all styling and positioning, etc. myself).

<div>something to display</div>