A Difficulty in Table Data Grid Scrren design

see....I have to design a page which looks like a metrics...in the column part it is having all the designation listed and in the row part it is having all the plant name.....now the intersecting cell will contain the link Assign/Modify. Upon Clicking that link user will be presented with a Dialogwindow in which he can select the user and assign the selected user for the selected plant and Designation. In the dialogwindow when you Press assign user button....it should not update immediately into the database but it should store that value for that cell temporarily and when Admin presses finally the Submit button all the values stored into these table cells should be updated. Only those cell values which are changed should be updated, not all the cell values......the Problem is we need to store the temporary value for the cells and in one shot when Admin presse the Submit button it should Update all the Updated cellls......Difficulty lies in storing the values for celll.....coz we need to use something like structure to store the values and in Javascript there is nothing like structure........and also the tracking which all cells are updated.....coz say....if it is some 50 by 50 metrics then we can not update all the 2500 cells.....wherein user might have chnged just a very few Cell values......

I am searching for the solution from past 4 days and still I haven't come to any conclusion.......

I hope u guies have understood my Problem and will try to help me in finding the solution for this, incase u or your colleage have worked on similiar kind of problem......

Thanks a lot for atlest reding my Problem......incase if you have an elegant solution for this then please provide it.