To download the latest production or development release of the JsPHP library, navigate to the functions tab and then select the functions (or categories of functions) that you wish to include in your version of the library. Then at the bottom of the page choose whether you want the latest production release, or the latest development release, and then click the Download button. If the functions you select are dependent on other functions, those additional functions will automatically be included in your download -- you don't need to manually include dependencies, those are included automatically. You just select the functions that you wish to be able to use from your own code.
The production release is the 'stable' release that includes only versions of functions that have gone through the testing and and quality assurance process. The development release includes the latest version of functions regardless of their release status. So if you're just checking out the code and you don't want to browse it on the www.jsphp.com website, then choose the development release. If you're planning to use the library in a production environment it's probably best to choose the production release.