HTML5 pattern attribute throws console errors

[ppowell777]

I have created an HTML page that produces a form with fields that have 'pattern=".."' attributes, however, before JavaScript can take over and remove the pattern attributes in favor of JavaScript validation, HTML5 itself, via Chrome, throws console errors trying to validate the regular expressions, any regular expressions, all of them fail: There is no "/v" in my pattern; there are only single backslashes in the pattern, and JavaScript successfully removes the pattern attributes from every form field only AFTER the errors are logged in the console. I have no idea why this is happening. Is this a Chrome bug, an HTML5 bug, or something I missed?

Pattern attribute value [-a-zA-Z'\s\.]+ is not a valid regular expression: Uncaught SyntaxError: Invalid regular expression: /[-a-zA-Z'\s\.]+/v: Invalid character in character class