php I need to write a json_encode function equivalent

[philiptibs]

I'm trying to use webspace provided by my university. They are currently using an outdated version of php, 5.1 I think. Anyway it doesn't have a json_encode function, however, I need a json_encode function (or equivalent) for my code to work. So if anyone could explain to me the syntax for the return of the json_encode function or point me to a website that explains it nicely it'd be much appreciated.Thanks