Download Prototype

Latest stable version

Download Prototype 1.7.3 (September 22, 2015)

Prototype development

You can browse the source code at our GitHub repository.

If you want the full development package (including unit tests), you can use Git to clone the source code:

git clone git://

Build the complete “prototype.js” file with the rake dist command. You can find more details about this in the contribution guide.


The latest version of Prototype is compatible with the following browsers:

Browser Version(s)
Mozilla Firefox ≥ 1.5
Microsoft Internet Explorer for Windows ≥ 6.0
Microsoft Edge (all versions)
Apple Safari ≥ 2.0.4
Google Chrome ≥ 1.0
Opera ≥ 9.25

Older versions