Script Lab is a tool for anyone who wants to learn about writing add-ins for Excel, Word, or PowerPoint. The focus is the Office JavaScript API, which is the technology you need for building Office add-ins that run across platforms. Maybe you’re an experienced Office developer and you want to quickly prototype a feature for your add-in. Or maybe you’ve never tried writing code for Office and you just want to play with a sample and tweak it to learn more. Either way, Script Lab is for you. More info about Script Lab: https://dev.office.com/blogs/script-lab-a-microsoft-garage-project
