To scroll up and down on your web page, you have the choice between the directional arrows on your keyboard, the vertical and horizontal scroll bars in the window which can be used with the mouse, or the mouse wheel. Why not configure your browser to automatically scroll for you?
To do this, you simply have to go to the top of the page and click on the mousse scroll wheel. A cursor will appear. Now you have to slightly move the mouse up and down for the automatic scrolling to begin.
Two examples can be seen below with the Firefox and Internet Explorer web browsers: