You don't know the length of this col

This works by forcing the wrapper to grow height for its floated children (3 columns in this case) by overflow: hidden. There are other ways to do this.

Here I make a simple 1px high background gif to the wrapper. There are just enough pixels across of the yellow to fill the left col, 1px of black to make like a border (might as well be hung for a sheep as for a lamb <g>) and then as many pixels as the middle column needs. Another one black px for a border (or separator) and a third colour for the rest.

The third colour is not strictly necessary and made here for no particular good reason. What is easily done is to make the wrapper have a background colour wgich can serve as one of the columns colour (often the last to the right is most convenient.

You don't know the length of this col

This works by forcing the wrapper to grow height for its floated children (3 columns in this case) by overflow: hidden. There are other ways to do this.

Here I make a simple 1px high background gif to the wrapper. There are just enough pixels across of the yellow to fill the left col, 1px of black to make like a border (might as well be hung for a sheep as for a lamb <g>) and then as many pixels as the middle column needs. Another one black px for a border (or separator) and a third colour for the rest.

The third colour is not strictly necessary and made here for no particular good reason. What is easily done is to make the wrapper have a background colour wgich can serve as one of the columns colour (often the last to the right is most convenient.

There are many ways to go with this sort of technique. You don't have to have the borders imaged. (a couple of pxels are involved here). And you don't have to be calculating so precisely in making the gifs, you can make two or three separate gifs sure to be wider than needed and use them as background to the columns.

You don't know the length of this col

This works by forcing the wrapper to grow height for its floated children (3 columns in this case) by overflow: hidden. There are other ways to do this.

There are many ways to go with this sort of technique. You don't have to have the borders imaged.

And, doubtless, you can combine some of the techniques from the simple tactics page with this one.