I am building a web application and I need to create a feedback form widget so the users can put it in their websites and all the submitted data will be saved in my web application. I also need to have authentication in the widget before the user can submit the information (using my application login form or a facebook account for example).

I have never build something like this. What is the best way?. I am not really conformtable with raw javascript. But if i use jquery it may conflict with the client´s page. And what about cross domain requests?.

Note that the first version of my widget should be in a popup.

Thanks for your help.