This requires a mouse with scrolling wheel.To do this:
>>Press and hold Ctrl key scroll up to zoom in (increase font size) and scroll down(decrease font size) to zoom out.
Second method:>>Press Ctrl and | + |(plus) key to zoom in and Ctrl and | - |(minus) key to zoom out.
>>To reset the web page press Ctrl + 0 (zero)
*This is very useful while printing a webpage