In simple terms, Cordova is the piece of software that stitches the web application and the native application together. The Apache Cordova website states that:

Apache Cordova does not just stitch the web app with the native app, but it also provides a set of APIs written in JavaScript to interact with the native features of the device. Yes, you can use JavaScript to access your camera, take a picture, and send it in an e-mail. Sounds exciting, right?

To get a better understanding of what is happening, let's take a look at the following image:

As you can see, we have a web view where the HTML/CSS/JS code gets executed. This code can be a simple standalone piece of user interface; at best you are making an AJAX request to get some data from a remote server. Or, this code can do much more, like talking to the Bluetooth of the device and getting the list of devices in...