// Javascript Numeric EditMask
// Written By John McGlothlin - Patoooey@optonline.net
// April 7th, 2004
// downloaded from: http://www.developerfusion.co.uk/show/5630

// simple RegEx patterns to make life easy.

var reOneOrMoreDigits = /[\d+]/;
var reNoDigits = /[^\d]/gi;

function doMask(textBox) {
	var keyCode = event.which ? event.which : event.keyCode;

	// enter, backspace, delete and tab keys are allowed thru

	if(keyCode == 13 || keyCode == 8 || keyCode == 9 || keyCode == 46)
		return true;

	// get character from keyCode....dealing with the "Numeric KeyPad" 
	// keyCodes so that it can be used

	var keyCharacter = cleanKeyCode(keyCode);

	// grab the textBox value and the mask
	var val = textBox.value;
	var mask = textBox.mask;

	// simple Regex to check if key is a digit

	if(reOneOrMoreDigits.test(keyCharacter) == false)
		return false;

	// get value minus any masking by removing all non-numerics
	val = val.replace(reNoDigits,'');			

	// add current keystroke
	val += keyCharacter;

	// mask it...val holds the existing TextBox.value + the current keystroke
	textBox.value = val.maskValue(mask);

	setCaretAtEnd(textBox);

	return false;
}

// puts starting chars in field

function onFocusMask(textBox) {
	var val = textBox.value;
	var mask = textBox.mask;

	if(val.length == 0 || val == null) {
		var i = mask.indexOf('#');
		textBox.value = mask.substring(0,i);
	}

	setCaretAtEnd(textBox);

	// set just in case.
	textBox.maxlength = mask.length;
}

// blank field if no digits entered

function onBlurMask(textBox) {
	var val = textBox.value;

	// if no digits....nada entered.....blank it.
	if(reOneOrMoreDigits.test(val) == false) {
		textBox.value = '';
	}

}

String.prototype.maskValue = function(mask) {
	var retVal = mask;
	var val = this;

	//loop thru mask and replace #'s with current value one at a time
	// better way of doing this ???

	for(var i=0;i<val.length;i++) {
		retVal = retVal.replace(/#/i, val.charAt(i));
	}

	// get rid of rest of #'s

	retVal = retVal.replace(/#/gi, "");

	return retVal;

}

// The Numeric KeyPad returns keyCodes that ain't all that workable.

//

// ie: KeyPad '1' returns keyCode 97 which String.fromCharCode converts to an 'a'.

//

// This cheesy way allows the Numeric KeyPad to be used

function cleanKeyCode(key)

{

	switch(key)

	{

		case 96: return "0"; break;

		case 97: return "1"; break;

		case 98: return "2"; break;

		case 99: return "3"; break;

		case 100: return "4"; break;

		case 101: return "5"; break;

		case 102: return "6"; break;

		case 103: return "7"; break;

		case 104: return "8"; break;

		case 105: return "9"; break;

		default: return String.fromCharCode(key); break;

	}

}

// From:

// http://www.faqts.com/knowledge_base/view.phtml/aid/1159/fid/130

function setCaretAtEnd (field) {

  if (field.createTextRange) {

    var r = field.createTextRange();

    r.moveStart('character', field.value.length);

    r.collapse();

    r.select();

  }

}