JavaScript regex + jQuery to match alert if arabic characters in input textbox

This fiddle shows how to use a regular expression to not allow only arabic letters in an input field For the original post, go here: http://www.leniel.net/2012/10/javascript-regex-jquery-to-match-only-english-characters-in-input-textbox.html

HTML

<input id="mytextbox" style="width:300px" placeholder="Only non russian letters are allowed here..."> JavaScript regex + jQuery to match on

CSS

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JavaScript

f$("#mytextbox").on("keypress", function(event) {

    // Disallow anything not matching the regex pattern (A to Z uppercase, a to z lowercase and white space)
    // For more on JavaScript Regular Expressions, look here: https://developer.mozilla.org/en-US/docs/JavaScript/Guide/Regular_Expressions
    var arabicAlphabet = /[\u0600-\u06ff]|[\u0750-\u077f]|[\ufb50-\ufc3f]|[\ufe70-\ufefc]/g;
    //var cyrillicAlphabet = /[\u0400-\u04ff]|[\u0500-\u052f]|[\u2de0-\u2dff]|[\ua640-\ua69f]|[\u1d2b-\u1d78]/g;
    // Retrieving the key from the char code passed in event.which
    // For more info on even.which, look here: http://stackoverflow.com/q/3050984/114029
    var key = String.fromCharCode(event.which);
    
    //alert(event.keyCode);
    
    // For the keyCodes, look here: http://stackoverflow.com/a/3781360/114029
    // keyCode == 8  is backspace
    // keyCode == 37 is left arrow
    // keyCode == 39 is right arrow
    // englishAlphabetAndWhiteSpace.test(key) does the matching, that is, test the key just typed against the regex pattern
    if (event.keyCode == 8 || event.keyCode == 37 || event.keyCode == 39 || !cyrillicAlphabet.test(key)) {
        return true;
    }

    // If we got this far, just return false because a disallowed key was typed.
    alert("Russian text detected - Please enter your details in english")
    return false;
});

$('#mytextbox').on("paste",function(e)
{
    e.preventDefault();
});