<form id="customerForm">
<label>
First Name:
<input id="firstName" required />
</label>
<label>
Social Security Number:
<input id="ssn" required pattern="^d{3}-d{2}-d{4}$"
title="Expected pattern is ###-##-####" />
</label>
<input type="submit" />
</form>
When I try that document in Chrome, it accepts the conditions and shows the error, as expected.
But when I try that document in Safari, it shows no error.
At this time, Safari doesn't support the "required" input attribute. http://caniuse.com/#search=required
To use the 'required' attribute on Safari, You can use 'webshim'
1 - Download webshim
2 - Put this code :
<head>
<script src="js/jquery.js"></script>
<script src="js-webshim/minified/polyfiller.js"></script>
<script>
webshim.activeLang('en');
webshims.polyfill('forms');
webshims.cfg.no$Switch = true;
</script>
</head>