checkbox: enter should submit form and not toggle

[Splaktar]

Bug

CodePen and steps to reproduce the issue:

CodePen Demo which demonstrates the issue:

https://codepen.io/Splaktar/pen/ZVjWRJ?editors=1010#0

Detailed Reproduction Steps:

1. Focus the first checkbox (input type="checkbox") and press the Enter key on the keyboard
2. Note that the form is submitted and the browser generates a warning for a required field
3. Focus the second checkbox (md-checkbox) and press the Enter key on the keyboard
4. Note that the form is not submitted and the checkbox value is toggled

What is the expected behavior?

Spacebar should toggle checkboxes. Enter should submit the form.

What is the current behavior?

For md-checkbox, the Enter key toggles the checkbox.

What is the use-case or motivation for changing an existing behavior?

Consistency with a11y and HTML standards.

Which versions of AngularJS, Material, OS, and browsers are affected?

• AngularJS: 1.7.5
• AngularJS Material: 1.1.12
• OS: macOS
• Browsers: Chrome 71

Is there anything else we should know? Stack Traces, Screenshots, etc.

Thanks to @codymikol for pointing this out.

[codymikol]

@Splaktar this should be good to go 🐔