An important goal of page design is to make websites viewable by as many visitors as possible, despite monitor resolutions and differences in display sizes between browsers, systems and platforms. Three methods are commonly used or combined to present visitors with a similar experience regardless of combination of system and browser they use to view web pages. Based upon a site visitor profile or Internet average profile, the sitebuilder selects one of the smaller resolutions, limiting page width to a specific size. Often a resolution of 640 X 480 is chosen - the smallest resolution in common desktop usage, and also generally viewable by most laptop systems.
Pages designed for lower monitor resolution are also viewable by monitors set to higher resolution.
Monitors with higher settings simply add blank space to the area outside the content. It is recommended that content be centered, so that an equal blank area appears on both sides of the viewers screen, no matter which resolution the page is viewed in. The amount of blank space will be individually determined by the visitors browser. The HTML standard allows widths of tables and forms to be defined as a specific number of pixels, or as a percentage of the browser window. By using the percentage option, the elements defined are seen in relationship to the viewers own browser window.