How to use regular expression to validate Chinese input?

Question

The thing is I need to treat this kind of Chinese input as invalid in client side validation:

Input is invalid when any English character mixed with any Chinese character and spaces has a total length >=10.

Let's say : "你的a你的a你的a你" or "你的你的你的你" (length is 10) is invalid. But "你的a你的a你的a" (length is 9) is OK.

I am using both Javascript to do client side validation and Java to do the server side. So I suppose applying the regular expression on both should be perfect.

Can anyone give some hints how to write the rules in regular expression?

what's your with space meaning, and what you have try? – LF00 Oct 18 '16 at 04:41 — LF00, Oct 18 '16 at 04:41
what about the other characters like ascii? – LF00 Oct 18 '16 at 04:46 — LF00, Oct 18 '16 at 04:46

score 18 · Accepted Answer · edited Sep 15 '22 at 14:52

18

From What's the complete range for Chinese characters in Unicode?, the CJK unicode ranges are:

Block                                   Range       Comment
--------------------------------------- ----------- ----------------------------------------------------
CJK Unified Ideographs                  4E00-9FFF   Common
CJK Unified Ideographs Extension A      3400-4DBF   Rare
CJK Unified Ideographs Extension B      20000-2A6DF Rare, historic
CJK Unified Ideographs Extension C      2A700–2B73F Rare, historic
CJK Unified Ideographs Extension D      2B740–2B81F Uncommon, some in current use
CJK Unified Ideographs Extension E      2B820–2CEAF Rare, historic
CJK Compatibility Ideographs            F900-FAFF   Duplicates, unifiable variants, corporate characters
CJK Compatibility Ideographs Supplement 2F800-2FA1F Unifiable variants
CJK Symbols and Punctuation             3000-303F

You probably want to allow code points from the Unicode blocks CJK Unified Ideographs and CJK Unified Ideographs Extension A.

This regex will match 0 to 9 spaces, ideographic spaces (U+3000), A-Z letters, or code points in those 2 CJK blocks.

/^[ A-Za-z\u3000-\u303F\u3400-\u4DBF\u4E00-\u9FFF]{0,9}$/

The ideographs are listed in:

However, you may as well add more blocks.

Code:

function has10OrLessCJK(text) {
    return /^[ A-Za-z\u3000-\u303F\u3400-\u4DBF\u4E00-\u9FFF]{0,9}$/.test(text);
}

function checkValidation(value) {
    var valid = document.getElementById("valid");
    if (has10OrLessCJK(value)) {
        valid.innerText = "Valid";
    } else {
        valid.innerText = "Invalid";
    }
}

<input type="text" 
       style="width:100%"
       oninput="checkValidation(this.value)"
       value="你的a你的a你的a">

<div id="valid">
    Valid
</div>

edited Sep 15 '22 at 14:52

weakish

28,682
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answered Oct 18 '16 at 05:02

Mariano

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Thx. this really give me some hints. I have just updated the question for a much clear description . Can you please take a look and advise ? – jm li Oct 18 '16 at 10:50
@jmli I edited the answer to include letters A-Z and a-z. Notice now it will consider an empty string as valid. Also, it won't allow 0-9 numbers or punctuation such as `a!b-c(d)3` (considered invalid). – Mariano Oct 18 '16 at 11:12
it's helpful. Apart from the exisiting rules, if only Chinese input(without any digit nor English char) is considered as valid. Is it possible to define an "or" checking by using Regex? – jm li Oct 18 '16 at 12:51
I mean pure Chinese without any length constriction – jm li Oct 18 '16 at 12:54
@jmli **[Alternation](http://www.regular-expressions.info/alternation.html)**: `/patternA|patternB/`... E.g. `/^[ \u3000\u3400-\u4DBF\u4E00-\u9FFF]+$|^[ A-Za-z\u3000\u3400-\u4DBF\u4E00-\u9FFF]{0,9}$/` – Mariano Oct 18 '16 at 12:59
@Mariano Where is the question mark like char located this one ？. I need to add that to the validation? – Helen Araya Jun 11 '20 at 20:04
@AmeteBlessed the FULLWIDTH QUESTION MARK (U+FF1F) is included in the [Halfwidth and Fullwidth Forms Block](https://www.fileformat.info/info/unicode/block/halfwidth_and_fullwidth_forms/list.htm) (FF01 - FFEE)... Yes, you can add that character to the regex as `\uFF1F`, or the whole block as `\uFF01-\uFFEE`. – Mariano Jun 13 '20 at 04:03
I would recommend that the table be removed from this answer, and referenced in the original question, as it has been updated, and the version represented here has errors. – Calion Oct 30 '22 at 15:01

How to use regular expression to validate Chinese input?

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