Save table td's in database

Question

In Manage categories I added a custom tab, now I want to save the data that I change in that tab.

Answer 1

The easy way:

You should add that custom data as category attributes, then any change should save the same as other attributes

You can find several references about installing a category attribute in Google, for instance this question in this site add-custom-attribute-for-category

If you don't use category attributes, then it becomes more complex... you should create your own database table to store your data, observe category save() event to store the data in your table, and then observe category load() event to add your data to category