I want a two-column div layout, where each one can have variable width e.g.
Have a look at the available CSS layout frameworks. I would recommend Simpl or, the slightly more complex, Blueprint framework.
If you are using Simpl (which involves importing just one simpl.css file), you can do this:
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View
, for a 50-50 layout, or :
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, for a 25-75 one.
It's that simple.