I have to close many cells each time before I export a notebook to HTML since I do not want to display many code cells and other cells.  

I select each cell one by one, and do `cell->cell properties->open` to uncheck it, so it closes. Then I export to html. Then I have to go reverse the whole process one by one again. I do this many times during the day.

I am getting tired of doing this. I know in V9 there is now a cell API so I am sure there is a way to program this where one will add each cell into some cell group, and then issue a command to open or close all cells.

But, is there a way, from the notebook UI, a way to say to Mathematica: please select all closed cells. Then when they are selected, I can go use the UI to change the property of all selected cells at once using the cell->... as above.

There should something like this. But I do not see it. I am using V9

thank you