How do I work with dates from URL and POST?

["RichieWhite" <webforumsuser@xxxxxxxxxxxxxx>]

When I pass the same date from an <A> tag and a form <input> tag, the results 
are different.
 They look the same, but the URL variable isn't in the same format when you use 
the result in a calculation.

 See http://www.fishingguidenow.com/datetest.cfm

 Please help me find a way to consistently calculate the results whether they 
come from a form or a URL.