I assume you taking about framesets
there are 3 ways to set a frames size:
in pixels: ("20" or "20px") this way of setting ensures that the frame has the same size no matter which resolution used.
it is useful if you e.g. want the frame to be at a height of just one text line
in percent: ("20%") ensures that the frame takes up a percentage of the screens size.
it is useful if you e.g. want your left frame to take up 1/3 of the screens width.
and then there is the asterisk: ("*") it tells the browser to use whatever is not used by other frames.
you can use any combination of these.
in this example:
will always have a height of 50 pixels.
will always take up 1/5 of the screens width
will then use what is left
(some older browsers had some problems rendering it the right way, so it could vary by a few pixels)
I suggest that you test, by viewing your page in different screen resolutions, what combination is best suited for your page.
you can just translate "%" to "px"
e.g. a framewidth at 20% wil be "200px" when viewed in 800x600 while it will be "256px" in "1024x768"
the size of a webpage depends on your resolution and browser.
it is equal to the white area you wil see if you enter "about
:blank" in your address-bar.
Here are some of the sizes:
in 800x600 using IE6 it's size is 800x465.
in 800x600 using N7.2 it's size is 800x444.
in 1024x768 using IE6 it's size is 1024x633.
in 1024x768 using N7.2 it's size is 1024x612.
hope this answers your questions