Constraint Your Data
Sometimes we do not know the size of the data or information that will be displayed on a page, or worse - we know it will be too large. Examples of such cases are: large data tables or code listing. Having page strech is not the best thing to happen obviously. Using IFrames is even worse.
This is where <div> tag and css style overflow come in handy. \ \ Put your troublesome area in a div like:
<div style="width:420px; height:200px; overflow:auto"> \ DATA OF ANY SIZE \ </div>
and you can rest assured that this area will have exactly 420x200 size, with nice vertical and/or horizontal scrollbars appearing if needed.