First, make sure you have subscribed to the Microsoft Translator API on Azure Marketplace and registered your application Azure DataMarket. For testing, you can use the free subscription which lets you submit up to 2 million characters a month. Registering your app will create a Client ID and a Client Secret which you need to get authorization.
In order to protect your Client Secret, you’ll need to write server-side code to get your access token. The access code is then passed to the Microsoft Translator API via AJAX.