How can I test if an input field contains foreign characters?
I have an input field in a form. Upon pushing submit, I want to validate to make sure the user entered non-latin characters only, so any foreign language characters, like Chinese among many others. Or at the very least test to make sure it does not contain any latin characters.
Could I use a regular expression for this? What would be the best approach for this?
I am validating in both javaScript and in PHP. What solutions can I use to check for foreign characters in the input field in both programm开发者_如何学Pythoning languages?
In PHP, you can check the Unicode property IsLatin
. That's probably closest to what you want.
So if preg_match('/\p{Latin}/u', $subject)
returns true, then there is at least one Latin character in your $subject
. See also this reference.
JavaScript doesn't support this; you'd have to contruct the valid Unicode ranges manually.
In Javascript, at least, you can use hex codes inside character range expressions:
var rlatins = /[\u0000-\u007f]/;
You can then test to see if there are any latin characters in a string like this:
if (rlatins.test(someString)) {
alert("ROMANI ITE DOMUM");
}
You're trying to check if all letters are not Latin, but you do accept accented letters.
A simple solution is to validate the string using the regex (this is useful if you have a validation plugin):
/^[^a-z]+$/i
^...$
- Match from start to end^[...]
- characters that are nota-z
- A though Z,+
- with at least one letter/i
- ignoring case (could also done/^[^a-zA-Z]+$/
)
Another option is simply to look for a letter:
/[a-z]/i
This regex will match if the string conatins a letter, so you can unvalidated it.
In JavaScript you can check that easily with if
:
var s = "שלום עולם";
if(s.match(/^[^a-z]+$/i){
}
or
if(!s.match(/[a-z]/i))
PHP has a different syntax and more security than JavaScript, but the regular expressions are the same.
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