Codeigniter function

Please see the attached screen shot. The shown form creates a new row in the database. I would like to add the js function to dynamically add a copy of the field "Enlace al video" (add a link beside the field "add more", when clicking on this, another field becomes visible, again with a link to add one more, etc) For each additional field, we need to create a new row on the db. That means, that if the user fills the form as is now, then we create one row with all the details. If the user adds one additional field, then we create 2 rows with all the details, row one with field 1 and row 2 with field 2. If the user adds 10 additional fields, then we create 10 rows, etc. Need this done today.