Use hidden iframe to implement form asynchronous commit without Ajax

Lifting Async, the first thing to think about is Ajax, but for scenarios where it's inconvenient to use Ajax, for example, we want to upload a file using Servlet 3.0, we also need to submit some form information, how to first commit the file asynchronously, and keep the form data from being refreshed.

Here's a way to implement a form asynchronous commit using a hidden iframe:

Target property setting for form label: target= "Hidden_frame"

Add an iframe inside the form form:

<iframe name= ' hidden_frame ' id= "hidden_frame" style= ' Display:none ' ></iframe>

Therefore, after clicking the Submit button, the Servlet,servlet execution of the action will navigate to the hidden IFrame, the page will not change, and the form data remains, thus avoiding jumping to a blank page.