Scroll it - A Javascript bookmarklet to automatically scroll the page

Have you ever had trouble when trying to play a song in your guitar when reading the chords from a web site? Don’t you always need to stop playing to scroll the page?

Scroll It – it’s a very simple JavaScript created to solve this kind of problem! It makes automatic scrolls in the page in a very comfortable speed.

##How to use it?

1. Click and drag Scroll it to your bookmark bar in the browser; </del>

Unfortunately I needed to remove the Bookmarklet link. The Markdown compiler didn’t worked with it.

1. Go to the site that your want to use Scroll it;

2. Click on Scroll It in your bookmark bar. That’s all.

To stop the automatic scroll, you only need to click again on Scroll it in your bookmark bar. ;)

##The JavaScript source code

javascript:(function(){
	/* @author Pablo Cantero http://pablocantero.com */
	if(window.scrollIt === undefined){
		window.scrollIt = {
			intervalId: null
		};
	}
	function getScrollMaxSize(){
		return document.body.clientHeight;
	};
	function getScrollCurrentSize(){
		return document.documentElement.scrollTop;
	};
	window.scrollIt.initialSize = getScrollCurrentSize();
	window.scrollIt.scrolled = getScrollCurrentSize();
	var scroll = function(){
		window.scrollIt.scrolled += 10;
		window.scrollTo(0, window.scrollIt.scrolled);
		if(window.scrollIt.scrolled >= getScrollMaxSize()){
			window.scrollIt.scrolled = window.scrollIt.initialSize;
		}
	};
	var stop = function(){
		window.clearInterval(window.scrollIt.intervalId);
		window.scrollIt.intervalId = null;
	};
	var start = function(){
		window.scrollIt.intervalId = window.setInterval(scroll, 1000);
	};
	if(window.scrollIt.intervalId != null){
		stop();
	} else {
		start();
	};
})()

##Do you want to improve this JavaScript?

The project is available on github as an open source project.

github.com/phstc/scroll-it

You’re welcome to make your contributions and send them as a pull request.

Thanks to @rdgr.