A class to convert km/h to mph and knots and vice-versa. It can also parse speeds in a text and return the text with corrected and converted speeds. See the live demo at http://ultralight-airplanes.info/yspeed.html for better idea what can it do.

This is a javascript class that converts the HTML 5 Canvas element into interactive drawing board with tools etc. The code below contains the full class, but I recommend downloading the zip from http://re.trotoys.com/article/rocanvas/ because it contains CSS, images and samples. The code is Apache licensed so you can use it on your sites without any issues.

This is rather simple stuff yet I see it so rarely used. In any dating sites, health calculators, DIY stuff calculators etc they ask you to enter weight and height of something (or your own weight and height) only in their preferred measurement system (metric or Imperial). Boring! This simple javascript will convert the units and instantly fill the appropriate fields in the form.