Take a look at the following piece of code to see Submit binding in action.
Take a careful look at the above code. In the html view section we have two input fields whose value is bind to to num1 and num2 parameters of StudentModel via data-bind. The submit event of the form is bind with the sum function of the StudentModel. The sum function simply captures the value entered by the user in two input fields, adds the two and display their sum inside an alert box.
Now open the above page in browser, you shall see two text fields, enter any two numbers in the text field and you shall see their sum in the alert box in the output.
It is important here that if want to submit your form to server in normal manner, simply return true from submit binding.
Another important question arises here that why not simple use click event on the form button and handle it in the view model instead of using submit. The answer is that you can do so, but submit also allows you to generate submit event on enter press unlike click.