Disable Back functionality using history.forward
We can disable the back navigation by adding following code in the webpage. Now the catch here is that you have to add this code in all the pages where you want to avoid user to get back from previous page. For example user follows the navigation page1 -> page2. And you want to stop user from page2 to go back to page1. In this case all following code in page1.
The above code will trigger history.forward event for page1. Thus if user presses Back button on page2, he will be sent to page1. But the history.forward code on page1 pushes the user back to page2. Thus user will not be able to go back from page1.
Warn User if Back is Pressed
You may want to warn user if Back button is pressed. This works in most of the cases. If you have some unsaved form data, you might want to trigger a warning message to user if Back button is pressed.
Include this in your HTML page to popup a warning message.