Mac OS X increase or decrease a web browser font size
Contributed by macster 
Tagged: Apple Mac Some web pages may use a font size that doesn’t render properly in different browsers on various platforms. If you find yourself squinting at a web page, this simple keyboard shortcut can help.
To increase the font size of the current web page, press command + by holding down the command key (with the apple and the squiggly) and pressing a plus key (no shift required).
To reduce the font size, press command - (command and minus).
I’ve tested this with Safari and Firefox. It may work with other browsers and applications.
You may also like -
IE: How to Change Text Size
Opera Mini: Optimize Viewing By Reducing Text Size
Temp Text Size Change
Safari 5: How to Hack and Customize the Reader
Windows Live Mail 2011: How to Change the Default Font and Size
Mac OS X: Clear the DNS cache
Windows 7: How to Format Sticky Note Text
Mac OS X change the default web browser
Steven Vachon said on April 11, 2009
Modern browsers have replaced this functionality with full-page zoom. So, you’ll have to select a “Zoom Text Only” option beforehand. Also, keep in mind that most websites are not engineered with larger font sizes in mind. Because of this, many times the layout will break resulting in something that is not legible.
kterbo said on October 17, 2011
This worked for me on my macbook pro like a charm… even 7 years after this post. :) thanks