For those folks who would like to zoom in and zoom out of a page but do not have the luxury of an external mouse with a scroll button for a laptop. Worry no more.
Hold Ctrl key and drag two fingers across your touchpad. This will zoom out if you swipe upwards and zoom in if you swipe downwards. Tested on HP,Lenovo and Dell laptops.
Not sure about the others but go ahead and give it a try. If it works or doesn't ,do post in the comments with the make and model of your laptop to help others.