I have a browser-based calculator that I would like to license for others to use on their sites. Should I ask them to run it in an iframe or give them an embed code? (Will an embed code even work with a multi-page script?) Thanks!
Go with the iframe. It's a simpler solution, requires less effort from them and will be easier for you to update. Think about it this way, if you find out there's a security hole in your calculator you can just change it on your server and then every client will have an updated version. However, if they had embedded the code - not only are their servers vulnerable but you will have to contact each and every one of them to update their code.
No question, iframe. You can also embed a 'powered by' link so that your free calculator benefits your site with a backlink from everyone who uses it.