Content of HTML table cells can be dragged to another cell or another table. It isn't difficult to define onMouseMove handler and change top / left element styles to move the object. In case with tables, you will have to determine somehow destination cell. Attaching onMouseOver handler on TD elements will not work, because browser doesn't fire events to the elements beneath the dragged object.
School timetable is example of how to use REDIPS.drag library. Page layout contains two tables: left table with school subjects and timetable on the right. After subject is placed to the timetable, button in the same color will be displayed next to the subject (clone object).
REDIPS.drag was initially built to drag and drop table content. After publishing first version of REDIPS.drag, I received a lot of questions about dragging table rows also. Now is possible to drag and drop table rows as well as table content.
Here is list of keywords (mostly class names) used in REDIPS.drag library. Id of drag container(s) or table cell class names should be named properly to achieve needed functionality like cloning DIV elements, adding trash cell, mark cells, adding row handler or mark table as "nolayout". This post is appendix to the REDIPS.drag documentation post.
As I caught myself in process of writing PHP "log" function several times I have finally decided to create a simple Logging PHP class. After Logging class initialization, first call of lwrite method will open log file implicitly and write line to the file. Every other lwrite will use already opened file pointer until closing file with lclose.