/*****************************************
MaskInput(field: HTMLInputElement, mask: String): void 

Adds the mask to a field. 
- field: field that will receive the mask 
- mask:  mask that will be applied 

Default Rules
-------------
a = A-Z and 0-9 
A = A-Z, accents and 0-9 
9 = 0-9 
C = A-Z and accents 
c = A-Z 
* = Any character 

Special rules
-------------
E = (Except) exception 
O = (Only) only 

Mask creation
-------------
Simple masks: In this kind of mask the user can't type more characters than the amount of characters in the mask. 
Example: 
telephone = (99)9999-9999 
date = 99/99/9999 

Special mask "rule^exceptions": This kind of mask is composed ty two parts, separated by "^", the left side specified the rule and the right one, the exceptions for the selected rule. 
Example: 
9^abc = The rule is to accept only numbers "9" and the exception are the characters a, b and c 
c^123 = Accepts only a-z characters and the exception are the numbers 1, 2 and 3 

Use of the special rules: it's similar to the special mask, but the left side has a different meaning, can be "E" (any character, except...) and "O" (only...) 
Example: 
E^abc: Accepts any character, except a, b and c 
O^123: Only allows the characters 1, 2 e 3 

- Examples
var f = document.forms[0];
MaskInput(f.phone, "(99)9999-9999");
MaskInput(f.data, "99/99/9999");
MaskInput(f.etc, "Cc99-*C");
MaskInput(f.except, "E^abc");
MaskInput(f.only, "O^abc");
MaskInput(f.letter, "C^");
MaskInput(f.letter2, "C^ ");
MaskInput(f.number, "9^abc");
******************************************/

// Add Event Listener to DOM Object
addEvent = function(o, e, f, s)
{
	var r = o[r = "_" + (e = "on" + e)] = o[r] || (o[e] ? [[o[e], o]] : []), a, c, d;
	r[r.length] = [f, s || o], o[e] = function(e)
	{
		try
		{
			(e = e || event).preventDefault || (e.preventDefault = function(){e.returnValue = false;});
			e.stopPropagation || (e.stopPropagation = function(){e.cancelBubble = true;});
			e.target || (e.target = e.srcElement || null);
			e.key = (e.which + 1 || e.keyCode + 1) - 1 || 0;
		}
		catch(f){}
		for (d = 1, f = r.length; f; r[--f] && (a = r[f][0], o = r[f][1], a.call ? c = a.call(o, e) 
		 : (o._ = a, c = o._(e), o._ = null), d &= c !== false));
    return e = null, !!d;
  }
};

// Mask inputs
maskInput = function(f, m)
{
	function mask(e)
	{
		var patterns = {"1": /[A-Z]/i, "2": /[0-9]/, "4": /[\xC0-\xFF]/i, "8": /./ },
		rules = { "a": 3, "A": 7, "9": 2, "C":5, "c": 1, "*": 8};
    
		function accept(c, rule)
		{
			for(var i = 1, r = rules[rule] || 0; i <= r; i<<=1)
			if(r & i && patterns[i].test(c))
				break;
			return i <= r || c == rule;
    }
    
		var k, mC, r, c = String.fromCharCode(k = e.key), l = f.value.length;
		(!k || k == 8 ? 1 : (r = /^(.)\^(.*)$/.exec(m)) && (r[0] = r[2].indexOf(c) + 1) + 1 ?
			r[1] == "O" ? r[0] : r[1] == "E" ? !r[0] : accept(c, r[1]) || r[0]
      : (l = (f.value += m.substr(l, (r = /[A|9|C|\*]/i.exec(m.substr(l))) ?
    r.index : l)).length) < m.length && accept(c, m.charAt(l))) || e.preventDefault();
  }
  for (var i in !/^(.)\^(.*)$/.test(m) && (f.maxLength = m.length), {keypress: 0, keyup: 1})
    addEvent(f, i, mask);
};