From the wikipedia article on BDD:
BDD is a second-generation, outside-in, pull-based, multiple-stakeholder, multiple-scale, high-automation, agile me
Behavior driven development is similar to TDD software process but the advantage of BDD is that the tests/features are written in simple English language thus it give a chance to QA and stakeholder to participate in the process of development. It is focused on the behavior of the software thus test are run in browsers.
Here is the guide that explain BDD and its implementation very well. BDD Introduction and Implementation
You can use behat, browserstack to implement BDD in your development process.