AngularJS Validation doesn't check step-Restriction of a HTML number input - angularjs

Question

Why is AngularJS not checking the step="0.01" attribute of the second input? For min and max attributes it works perfectly, but not for the step attribute.
For example: The input 0,005 will evaluate submitNewEntryForm.submitNewEntryAmount.$valid to true, but it shouldn't.
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
<div ng-app="">
<form class="form-inline" name="submitNewEntryForm">
<div class="form-group" ng-class="submitNewEntryForm.submitNewEntrySubject.$valid ? 'has-success' : 'has-error'">
<label for="subject">Betreff:</label>
<input type="text" class="form-control" id="subject" required name="submitNewEntrySubject" ng-model="submitNewEntrySubject">
</div>
<div class="form-group" ng-class="submitNewEntryForm.submitNewEntryAmount.$valid ? 'has-success' : 'has-error'">
<label for="amount">Betrag:</label>
<input type="number" class="form-control" id="amount" required name="submitNewEntryAmount" ng-model="submitNewEntryAmount" step="0.01" min="0" max="99999">
</div>
<button type="submit" class="btn btn-primary" ng-disabled="!(submitNewEntryForm.submitNewEntrySubject.$valid && submitNewEntryForm.submitNewEntryAmount.$valid)" ng-click="">Submit</button>
</form>
</div>

Answer 1

Add regex, like \d+\.\d{0,2}
You can use HTML5 pattern="^\d+\.\d{0,2}$" or ng-pattern="^\d+\.\d{0,2}$". It changes error state without limiting html input to 2 decimal points.
To be strict, you should use ^\d{1,5}\.\d{,2}$
If you want number to have 2 decimal point but allow it to be without leading 0 like .01, you can use ^\d*\.\d{2}$

Answer 2

I didn't realize that there was a Angular directive for the step attribute. If you look at the documentation, it seems to be a very recent addition.
I find no mention of the step attribute until you get to a build of the un-released 1.5.9 version.
Latest version: https://docs.angularjs.org/api/ng/input/input%5Bnumber%5D
Notice in the "Usage" and "Arguments" sections that the step directive is listed. Now use the pull down menu in the upper left to change the version, and observe that there is no mention of the step directive.
Either this is a brand new, unreleased feature... or perhaps the documentation for older versions is not correct :)