WebIDE allows you to use Firefox's awesome developer tools for applications that run in the Simulator via WebIDE as well. To use them, simply click on the Settings icon (which looks like a wrench) beside the Install and Run icons that you used to get the app installed and running. This icon says Debug App on hovering the cursor over it. Click on this to reveal developer tools for the app that is running via WebIDE.
Click on Console, and you will see the message Hello Firefox, which we gave as the input in console.log() in the app.js file. Note that it also specifies the app ID of our application while displaying Hello Firefox. You may have noticed in the preceding illustration that I sent a command via the console, alert('Hello Firefox'), and it simultaneously executed the instruction in the app running in the simulator.
As you may have noticed, Firefox OS customizes the look and feel of components, such as the alert box (this is browser based). Our application...