html – Error due to unknown: "SyntaxError: invalid range in character class"



I have a page that contains an <iframe> of another, on this other page I have a simple HTML input element:

<input type="text" required="" pattern="[a-Z]{2,35}" tabindex="6" name="edtCidade" id="edtCidade">

I'm sure and I made sure that there is no event type assigned to it or code changing its properties.

However, every time I type, any key, it can be a number, it can be a letter, anything, every time I type it generates this error in the console:

SyntaxError: invalid range in character class


If I type "az123" I will get 5 SyntaxError errors in my browser console.


This error does not cause me any problems, it is insignificant but it is bothering me, and I would like to know the origin of it.


How to resolve this error? Why is he occasioned? I would like a detailed explanation.


The error is associated with regular expressions, being caused by a range aZ (lowercase and uppercase Z ) in the pattern attribute.

As the pattern attribute is an element of the input included in HTML5 , the expression will be executed even without any additional plugins or events.

To accept both uppercase and lowercase letters, use [a-zA-Z] , as there seems to be no way to make the default case insensitive .

Note : in Chrome this exception does not occur, it just skips validation. So I assume you are using Firefox. 🙂

Demo on JsFiddle

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