Add AJAX to a page

I have a table management site for restaraunts. The admin page (see iamge) is currently pure php. I can add tables by clicking in an empty space. I can edit the properties of a table by clicking on the table. I want to add AJAX functionality for two things: 1. I want to be able to drag & drop the tables in the grid 2. I want to be able to resize the tables by grabbing the corners of the table Also * I shall only be able to move tables to empty spots in the grid. * I shall not be able to resize a table so that it collides with an existing table in the grid.