function updateStrength(field) {
	var numbers=0;
	var lowercase=0;
	var uppercase=0;
	var special=0;
	
	var password = field.value;
	var elem = new getObj('pwstrength');
	
	for (var i=0; i<password.length;i++){
		chr = password.charAt(i);
		
		if (isNum(chr)) numbers=1;
		else if (isLower(chr)) lowercase=2;
		else if (isUpper(chr)) uppercase=2;
		else if (isSpecial(chr)) special=3;
		else { elem.obj.innerHTML = 'Error: Enkel de volgende speciale tekens zijn toegelaten: !|_-@#{},?;'; return 0;}
	}

	var score = numbers + lowercase + uppercase + special;
	
	if (password.length<4){
		score = 1;
	}
	
	
	elem.obj.innerHTML = "score: " + score;
	document.images["strength"].src = '/include/js/passwordChecker/strength'+score+'.png';
}

var numb = '0123456789';
var lwr = 'abcdefghijklmnopqrstuvwxyz';
var upr = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
var spec = '!|_-@#{},?;';
 
function isValid(parm,val) {
  if (parm == "") return false;
  for (i=0; i<parm.length; i++) {
    if (val.indexOf(parm.charAt(i),0) == -1) return false;
  }
  return true;
}
 
function isNum(parm) {return isValid(parm,numb);}
function isLower(parm) {return isValid(parm,lwr);}
function isUpper(parm) {return isValid(parm,upr);}
function isSpecial(parm) {return isValid(parm,spec);}