Container Margins / Centering
There's an issue with wrapping the whole ul element in index.html with say a <div style="width: 960px; margin: 0 auto;">, the images all jerk to the right on the first scroll.
I haven't had a chance to div into the script and see where the problem is, but if that sounds like something that might be a quick fix, I'd love to use the script, just need to center the content :-)
Great script, thanks for your work!
I had a similar problem - the background images would always jump 50px to the right on the first scroll and then stay there. Since I only need y-axis scrolling and I needed the background to always be centered, I simply updated line #130 from this:
$this.css({'backgroundPosition': parseInt(newXPos) + "px " + parseInt(newYPos) +"px"});
to this:
$this.css({'backgroundPosition': "50%" + parseInt(newYPos) +"px"});
I couldn't ever figure out where that 50px was coming from, but this solved my problem so I'm happy.
The 50 comes from lines 107 and 123.
107 says grab the 1st part of the position array and strip out non-numerical characters. So if you had '50%' in there to center your item, then you have '50' left after the replace. In line 123, its saying if we aren't parallaxing the x-axis, use the value we have after the replace, which by default the browser makes into 50px. If you want to keep your x position intact, you can change line 135 to
$this.css({'backgroundPosition': currentPosArray[0] + parseInt(newYPos) +"px"});
Now this wont keep your child items inside a container, you'd have to do some extra work to check where the parent is and adjust your child based on that.