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Can't Change Font Size in Internet Explorer
http://www.vistaarticles.com/articles/175/1/Can%26%2339%3Bt-Change-Font-Size-in-Internet-Explorer
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Published on 11/23/2006
 
When you click the Size button on the Standard Buttons toolbar, the font size on the Web page you are viewing may not change.

Can't Change Font Size in Internet Explorer
To work around this behavior, configure Internet Explorer to ignore font sizes specified on Web pages: 1. Start Internet Explorer.
2. On the Tools menu, click Internet Options.
3. On the General tab, click Accessibility.
4. Click to select the Ignore font sizes specified on Web pages check box.
5. Click OK twice.