Simple assignment javascript php etc

The page has a rectangular grid of n × m boxes, where n and m are parameters given by the user. There are t tiles of size less than the box height, but about equal to box width, which are arranged in rows at the bottom of page (the reservoir of tiles, t in number, where t may be greater than n× m) A tile can be dragged using mouse and placed in a box, empty or already having one or more tiles. If the height of the box needs to be re-adjusted to fit the incumbent tile, all boxes in that row will be resized accordingly. Multiple tiles shall appear linewise in the box, not sorted in any specific order. A tile can be moved from one box to another, or even back to bottom row (reservoir) by the user. Each tile has some text in it, which identifies it. This text has two parts – editable and non-editable text, e.g. non-editable is tile ID and name, editable is a descriptive field such as name of a movie and its director. All tiles may be placed in boxes in one session, or the session can be saved and resumed later. There may remain some boxes which are empty. User should have the option of locking a placement. Locked placements cannot be changed later. For a particular placement of tiles, all placement data is be exported to a csv file upon clicking the Export button: (row-id, col-id, tile-id) (for an empty box, tile-id will be null) The start-up data of n, m, t, and tile texts is to be read from a csv file, and rendered on page as per above description.