Time axis has wrong labels

[Google Code Exporter]

What steps will reproduce the problem?
1. Visit http://www.simile-widgets.org/timeplot/ 
2. Look at time axis.
3. Observe that time axis labels are off by one.

What is the expected output? What do you see instead?
Time axis labels should be the correct date.

What version of the product are you using? On what browser and what
operating system?
Browser: Opera, Safari.
OS: OSX 10.7.2

Original issue reported on code.google.com by [e-mail] on 17 Nov 2011 at 2:31