How to create something similar to the Google Calculator for a Search Site?

I'm interested in something like this - http://www.google.com/help/features.html#calculator

My best guess is that there's a calculator already on my server to process this info, but how can it be introduced through a search, i.e.:
calc: 1+1=

Thanks

 

You could create a javascript calculator or use server side scripting to create one in php or asp.

There will not be one preinstalled but I am sure there are plenty of free scripts out there.

Try
http://www.google.co.uk/search?q=php+calculator+script
http://www.google.co.uk/search?q=javascript+calculator+script

 

Thanks, but how about a server based one like Google? I know the scripts you are talking about but want to combine it into my search box.

 

You would need to write a script to recognise whether a calculation is being typed or a standard search query and then either use the search script or the calculation script.

in php you could recognise a pattern eg 2 + 2 = and if the search variable looks like this then use the calculation script.

Alternatively use the calculation script everytime but only output the result if it comes up with a numerical answer. If the answer is not numerical then output the standard search results.

 

Err Thanks again, I was actually looking for a script to implement rather than how it could be done.

Thanks anyway.