I have created a wordpress network which I use to host small client websites. I grant clients a custom user role. I would like to allow all my clients to add Iframes from google docs (Ie spreadsheets) and Paypal ('buy now') buttons.
I am aware that I could add unfiltered_html ability to my clients user roles but I don't want to completely open the floodgates to any and all HTML markup.
I'm also aware that I could add a number of different plugins that allow for similar abilities. However for simplicity I would prefer to rely on the Iframes and forms provided by Google and Paypal on their respective websites.
My question then, is: Is there anyway to allow users to add html from a list of allowed sources of my choosing?