Firefox input pattern regex range - html

Question

This is related to the same problem as this question:
Firefox error: Unable to check input because the pattern is not a valid regexp: invalid identity escape in regular expression
When using escaped characters in the <input> pattern attribute, Firefox throws these errors to the console:
Unable to check <input
pattern='^[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEFa-zA-Z\s\'-]{1,50}$'>
because the pattern is not a valid regexp: invalid identity escape in
regular expression
So when using the pattern attribute on an <input> field, the unicode characters no longer need to be escaped. In that case the user simply needs to stop escaping their characters and change \#\% to #%, problem solved.
I've got this somewhat more complicated regex pattern, what do I change it to to work in Firefox?
<input type="text" pattern="^[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEFa-zA-Z\s\'-]{1,50}$">
Essentially it's allowing for any string between 1..50 characters in length as long as all the characters are within these ranges:
\u00A0-\uD7FF
\uF900-\uFDCF
\uFDF0-\uFFEF
a-z
A-Z
as well as whitespace, apostrophes and hyphens. A quick search sees the \u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEFa part of it fairly widely used in all sorts of regexes. I just don't see exactly what to use instead of the escaped unicode character references here.

Answer 1

You need to remove the escaping backslash before the single quote.
Note that in a regular HTML5 pattern field, one does not have to use ^ and $ anchors at the pattern start/end as the HTML5 pattern attribute encloses the passed pattern with ^(?: and )$. However, as per your feedback, the Abide validation circumvents this and passes unanchored pattern to the regex engine. Thus, you should keep the anchors.
<input type="text" pattern="^[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEFa-zA-Z\s'-]{1,50}$">
A quick demo:
<form>
<input type="text" pattern="[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEFa-zA-Z\s'-]{1,50}">
<input type="submit">
</form>