//browser detection
var strUserAgent = navigator.userAgent.toLowerCase();
var isIE = strUserAgent.indexOf("msie") > -1;
var isNS6 = ( strUserAgent.indexOf("netscape6") > -1 || strUserAgent.indexOf("mozilla") > -1 );
var isNS4 = !isIE && !isNS6  && parseFloat(navigator.appVersion) < 5;

//regular expressions
var reValidChars = /\d/;
var reValidString = /^\d*$/;
var reKeyboardChars = /[\x00\x03\x08\x0D\x16\x18\x1A]/;
var reClipboardChars = /[cvxzr]/i;

//mask functions
function maskKeyPress(objEvent) {
	var iKeyCode, strKey, objInput;

	if (isIE) {
		iKeyCode = objEvent.keyCode;
		objInput = objEvent.srcElement;
	} else {
		iKeyCode = objEvent.which;
		objInput = objEvent.target;
	}

	strKey = String.fromCharCode(iKeyCode);
	
	// paste disabled
	if (isNS6 && objEvent.ctrlKey && strKey == 'v' ){
		Common.Class.add( objInput, 'alert' )
		setTimeout( function () { Common.Class.remove(objInput,'alert') }, 50 )
		return false;
	}

	if (isValid(objInput.value)) {
		objInput.validValue = objInput.value;
		if (!reValidChars.test(strKey) && !reKeyboardChars.test(strKey) && !checkClipboardCode(objEvent, strKey)) {
			Common.Class.add( objInput, 'alert' )
			setTimeout( function () { Common.Class.remove(objInput,'alert') }, 50 )
			return false;
		}
	} else {
		objInput.value = objInput.validValue;
		return false;
	}

	if ( iKeyCode == 0x0D ) objInput.blur();

}

function checkClipboardCode(objEvent, strKey) {
	if (isNS6)
		return objEvent.ctrlKey && reClipboardChars.test(strKey);
	else
		return false;
}

function isValid(strValue) {
	return reValidString.test(strValue) || strValue.length == 0;
}

function maskChange(objEvent) {
	var objInput;

	if (isIE) {
		objInput = objEvent.srcElement;
	} else {
		objInput = objEvent.target;
	}

	if (!isValid(objInput.value)) {
		//alert("Invalid data");
		objInput.value = objInput.validValue || "";
		objInput.focus();
		objInput.select();
	} else {
		objInput.validValue = objInput.value;
	}
}

function maskPaste(objEvent) {
	var strPasteData = window.clipboardData.getData("Text");
	var objInput = objEvent.srcElement;

	if (!isValid(strPasteData)) {
		Common.Class.add( objInput, 'alert' )
		setTimeout( function () { Common.Class.remove(objInput,'alert') }, 50 )
		return false;
	}
}