Button to change the order display of tag cloud

Dear all,

Thanks for spending a few seconds to read these lines.
My question is simple, but the answers too complex for me to be found.

I divided my page into 2 divs floating side to side.
On the left part, I put a tag cloud of post entries
On the right side, the posts of the tag we clicked on.

I would like to make a button, lets say “wide view”, in order to increase the size of the posts on the right side, while still keeping the tagcloud running on the left side.

is this possible? if yes, what are your thoughts to achieve this?
php would be better than js…