function maxCaracteres(campo, nCaracteres){
	if(campo.value.length >= nCaracteres -1){
		campo.value = campo.value.substring(0, nCaracteres -2);
		alert("Atención:\nPermitidos máximo " + nCaracteres + " caracteres.\t");
	}
}
function displayCtrl(ctrl){
	if ( document.getElementById ) {
		var target = document.getElementById( ctrl );
		if ( target != null ) {
			target.style.display = ( target.style.display != "none" ) ? "none" : "";
		}
	}
}
function Left(str, n){
	if (n <= 0)
	    return "";
	else if (n > String(str).length)
	    return str;
	else
	    return String(str).substring(0,n);
}
function Right(str, n){
    if (n <= 0)
       return "";
    else if (n > String(str).length)
       return str;
    else {
       var iLen = String(str).length;
       return String(str).substring(iLen, iLen - n);
    }
}
function LTrim(sString){
	while (sString.substring(0,1) == ' ')
	{
		sString = sString.substring(1, sString.length);
	}
	return sString;
}
function RTrim(sString){
	while (sString.substring(sString.length-1, sString.length) == ' ')
	{
		sString = sString.substring(0,sString.length-1);
	}
	return sString;
}
function Trim(sString){
	sString = LTrim(sString);
	sString = RTrim(sString);
	return sString;
}
function IsEmail(email){
	var regx=new RegExp("^[\\w\.=-]+@[\\w\\.-]+\\.[a-zA-Z]{2,4}$");
    return regx.test(email);
}
function esDigito(sChr){
    var sCod = sChr.charCodeAt(0);
    return ((sCod > 47) && (sCod < 58));
}
function valSep(oTxt){
    var bOk = false;
    var sep1 = oTxt.charAt(2);
    var sep2 = oTxt.charAt(5);
    bOk = bOk || ((sep1 == "-") && (sep2 == "-"));
    bOk = bOk || ((sep1 == "/") && (sep2 == "/"));
    return bOk;
}
function finMes(oTxt){
    var nMes = parseInt(oTxt.substr(3, 2), 10);
    var nAno = parseInt(oTxt.substr(6), 10);
    var nRes = 0;
    switch (nMes){
     case 1: nRes = 31; break;
     case 2: nRes = 28; break;
     case 3: nRes = 31; break;
     case 4: nRes = 30; break;
     case 5: nRes = 31; break;
     case 6: nRes = 30; break;
     case 7: nRes = 31; break;
     case 8: nRes = 31; break;
     case 9: nRes = 30; break;
     case 10: nRes = 31; break;
     case 11: nRes = 30; break;
     case 12: nRes = 31; break;
    }
    return nRes + (((nMes == 2) && (nAno % 4) == 0)? 1: 0);
}
function valDia(oTxt){
    var bOk = false;
    var nDia = parseInt(oTxt.substr(0, 2), 10);
    bOk = bOk || ((nDia >= 1) && (nDia <= finMes(oTxt)));
    return bOk;
}
function valMes(oTxt){
    var bOk = false;
    var nMes = parseInt(oTxt.substr(3, 2), 10);
    bOk = bOk || ((nMes >= 1) && (nMes <= 12));
    return bOk;
}
function valAno(oTxt){
	var bOk = true;
    var nAno = oTxt.substr(6);
    bOk = bOk && ((nAno.length == 2) || (nAno.length == 4));
    if (bOk){
     for (var i = 0; i < nAno.length; i++){
      bOk = bOk && esDigito(nAno.charAt(i));
     }
    }
    return bOk;
}
function IsDate(oTxt){
    var bOk = true;
    if (oTxt != ""){
		bOk = bOk && (valAno(oTxt));
		bOk = bOk && (valMes(oTxt));
		bOk = bOk && (valDia(oTxt));
		bOk = bOk && (valSep(oTxt));
		if(bOk) return true;
	}
	return false;
}