Angular 4 enable HTML5 validation : <p>I want to use HTML5 validation in Angular 4 rather than their form's based validation/reactive validation.  I want to keep the validation running in the browser. </p>

<p>It used to work in Angular 2, but since I've upgraded, I can't get even manually created forms without any angular directives to validate using HTML5.</p>

<p>For instance, this won't validate in the browser at all:</p>

<pre><code>&lt;form&gt;
&lt;h2&gt;Phone Number Validation&lt;/h2&gt;
&lt;label for="phonenum"&gt;Phone Number (format: xxxx-xxx-xxxx):&lt;/label&gt;&lt;br /&gt;
&lt;input id="phonenum" type="tel" pattern="^\d{4}-\d{3}-\d{4}$" required&gt;

&lt;input type="submit" value="Submit"&gt;

&lt;/form&gt;
</code></pre>
