add onclick alert for text?

Hey i made a website for a good friend based on html with php and database support. Since he is not tech savvy I made a little CMS using CKeditor. He built a table with some dates using CK now and asked me if it is possible to pop up a window if a viewer clicks a date in the table. I could personally do this in the source code of course but he can't and I am not going to edit everything for him! So is there a way to add a javascript alert onclickevent for a text in a "-Element" using the GUI of CKEditor? ??