Open any six Web pages at random and you'll get six different layouts and twice as many font styles and sizes.
The simplest way to make a page easier to read via the keyboard is to press Ctrl and the + (plus) and - (minus) keys to increase and decrease the size of text and usually images on the page. If you're browsing by mouse, press Ctrl and spin the scroll wheel up or down to change the size of a Web page's elements. You'll also find zoom-in and zoom-out options on the View menu in Firefox, IE, and Opera, and on Chrome's Tools menu.
(If you just want to maximize your view of the current page, move the browser's own components out of the way. In all four browsers, press F11 or click View > Full Screen to switch to full-screen mode. Press F11 again to return to the normal view. In Chrome, click the Tools icon in the top-right corner and choose Full screen.)
Put a finer point on your Web zooming
You don't have to stick with your browser's default zoom options. To create a custom-zoom setting in IE 8, click View > Zoom > Custom. You get a couple other zoom options in IE by clicking Tools > Internet Options > Advanced and looking in the Accessibility section. IE 8 also shows the current zoom percentage in the bottom right of the status bar and opens the zoom options when you click the button to the right of the number.
Internet Explorer users may have noticed a better zoom experience through IE 8's new Adaptive Zoom feature, which adjusts all the elements on a page so content doesn't flow off the screen to the right, for example. Saloni Mira Rai describes the technology on Microsoft's IEBlog. Even more detail about IE 8's improved zooming is available in an IEBlog post by Harel Williams.
Opera has used the same type of adaptive zoom for some time, but you can also customize the browser's zoom settings by clicking Tools > Preferences > Web Pages and adjusting the two options under "Choose image and zoom settings for new tabs."
Firefox's about:config options include settings for remembering the zoom level of specific sites and for changing the percentage zoom of each increment. Percy Cabello provides the details in "Tweak Firefox 3 full page zoom" on the Mozilla Link site.
Chrome doesn't let you customize its zoom options, but you can change the default font size and type by clicking the Tools icon, choosing Options > Under the Hood, scrolling to Web Content, and clicking Change Font and Language Settings.
Of course, you can also change the default fonts in Firefox (Tools > Options > Content), IE (Tools > Internet Options > General > Fonts), and Opera (Tools > Preferences > Web Pages). By default, these settings apply only to pages that don't specify fonts, and there aren't many of those around.
To override the page's font settings in IE, click Tools > Internet Options > Accessibility and check "Ignore font styles specified on Web pages" and "Ignore font sizes specified on Web pages."
To override a page's preset fonts in Firefox, click Tools > Options > Content, select the Advanced button under Fonts & Colors, and uncheck "Allow pages to choose their own fonts, instead of my selections above."
As far as I can tell, Opera and Chrome don't let you override the fonts specified by a site, but you can set the minimum font size in Opera by clicking Tools > Preferences > Advanced, choosing Fonts in the left pane, and changing the value of "Minimum font size (pixels)."
Firefox add-ons make zooming a breeze
Add zoom-in and zoom-out buttons to Firefox's status bar with the Zoom Page add-on. The simple utility also shows the current zoom percentage; right-click the number to zoom only text.
Get even more zoom options in Firefox with the NoSquint add-on developed by Jason Tackaberry. In addition to status-bar zoom-in/zoom-out buttons and zoom percentage, NoSquint lets you set the full and text zoom levels for specific sites, change the text and background colors, and disable backgrounds images altogether. You can also disable zooming with your mouse scroll wheel and change the default zoom from text and images to text only.
What I need is an add-on that monitors my level of eyestrain and adjusts the size of page elements accordingly. Even better, how about an add-on that automatically highlights the small nugget of information I'm actually looking for on the page? I'll zoom to that!