You can check your browser's HTML5 compatibility here:

http://html5test.com

To find out what the latest versions of the major browsers are visit:

 http://browsehappy.com/

Below is a list of supported browsers and how the size of text can be changed:



Microsoft Internet Explorer- Version 11.0 or above

From the top menu select View
A list of options will appear in the drop down menu, choose "text size" 
another drop down menu should appear with options including "small", "medium", "large", "largest"



Mozilla Firefox - Version 20.0 or above

To make text larger press Ctrl+
Keep repeating until the text is enlarged to your requirements
To make text smaller press Ctrl -



Apple Safari - Version 5.0 or above

To make text larger press Ctrl+
Keep repeating until the text is enlarged to your requirements
To make text smaller press Ctrl -



Google Chrome - Version 25.0 or above

To make text larger press Ctrl++ 
To make text smaller press Ctrl -- 
To return text to normal size press 
Ctrl + 0