Translate javascript to Excel VBA

On http://www.dauntless-soft.com/products/freebies/trueairspeedcalculator/ is a small online application to perform a few mathematical calculations. I downloaded the jacascript sourcecode and prepared an Excel workbook. The javascript code is in a textbox on a worksheet. Unfortunately I fail to translate the mathematical part of the javascript code to VBA. I am looking for a freelancer who can complete the Excel workbook.