Chinese character forbid - php

Question

I have a web form, and I'd want the user while filling the form to not include any Chinese single quotes/double quotes in a textarea, how can I do that ?

Answer 1

You could get the form content and check it against a list of non accepted characters:
$formContent = $_GET["formcontent"];
$badCharacters = array("'", "‘", "“");
$cleanResult = str_replace($badCharacters, "", $formContent);
The bad characters array has the quote signs you dont like (if they are the standard quotes you will need to escape them) then the str_replace function goes through the form data replacing each one with an empty string. You should do proper escaping and security before this of course.

Answer 2

To prevent user from typing into form element you must use client side scripting aka JavaScript.
Simple way is handling the onkeypress event:
<textarea onkeypress="return CheckKey(event);"></textarea>​
And having such code:
var arrForbiddenCodes = [97, 98, 99];
function CheckKey(event) {
var keyCode = event.keyCode || event.which;
for (var i = 0; i < arrForbiddenCodes.length; i++) {
if (arrForbiddenCodes[i] === keyCode)
return false;
}
return true;
}​
This will block characters based on their key code - in the above code, the lower case "a", "b" and "c" letters will be blocked. To find key code of specific character, add alert(keyCode); to the function and just type that character into the textarea.
Live test case.

Answer 3

you could add some javascript that uses a regex to restrict the entry to alpha or alpha and numeric (or any additional characters you want).
<script language="javascript">
function blockChar()
{
var str = document.getElementById('txt').value;
if(str.match(^[a-zA-Z0-9]*$)) {
return true;
}
else {
return false;
}
}
</script>