You can check your browser's HTML5 compatibility here:
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