Split Panel using javascript

I'm trying to code a split panel, Left and r开发者_如何学Cight. Each will have a button which you can click on and it will toggle that panel, while expanding the other.

I am clueless as to where to start off? Is there an example that already does this?

Can someone help me out.

Thanks

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I created this example. Check it out http://jsbin.com/ekabe5. You can just change the style of the div to toggle or expand it.