Zoom with time working in but not out

[Mike Hancock]

https://jsfiddle.net/onykage/phz69nby/

for some reason this fiddle doesnt work.  But it works directly cut n paste in a browser.

It shows the code tho.  Issues are, if you get a tool tip for time it shows nan for any time output. 
and if you zoom out with works fine but if you try to zoom back in, the x-axis doesnt move.  which creates a really weird graph.

Anyone have any suggestions?

[Ced]

You left some php tags in the fiddle code.
The placeholder variable doesn't exist when you create yaxisLabel
You also don't need $(function() {}); in jsfiddle. The javascript runs after the page loads.