When you click the button, the following message window (window may be slightly different if you are using some other browser) would be displayed: -

In this case, click on to proceed with your submission.

However, the above message window would also be displayed when you try to exit the page without submitting your information. Remember that exiting the page without clicking the button may result in loss of your information. It is very important that you submit the information you typed into the form. Click in this case, to go back to the form with all your information filled in it so you can review it and submit it.