3.2.2 On Input
Make Web pages appear and operate in predictable ways.

About

When users do change on a web page setting, it should not open a popup window or cause a change of context. Making changes in context, Users who are easily distracted by changes or those who cannot figure out changes, can become confused because of changes in context.

So entering text into a text field, selecting a drop down menu or checking a check box change the setting of webpage, but activating a link or a button does not.

Example:

Before Rectification

image of selecting a choice and the form be submitted automatically

Here, When a user selects a choice and the form be submitted automatically, it can make the website very difficult for people with disabilities.

After Rectification

image of Activating a button when submitting a form

Activating a link or a button is a better option , since it gives the user control over when to submit the form.