var GLOBAL_BROWSER = getBrowser();

function getBrowser(){
  if (document.layers) return "NS";
  if (document.all) {
		var agt=navigator.userAgent.toLowerCase();
		var is_opera = (agt.indexOf("opera") != -1);
		var is_konq = (agt.indexOf("konqueror") != -1);
		if(is_opera) {
			return "OPR";
		} else {
			if(is_konq) {
				return "KONQ";
			} else {
				return "IE";
			}
		}
  }
  if (document.getElementById) return "MOZ";
  return "OTHER";
}

<!--
//var nav4 = window.Event ? true : false;
function onlyNumbers(evt){	
	var key = (GLOBAL_BROWSER != "IE") ? evt.which : evt.keyCode;	
	return (key <= 13 || (key >= 48 && key <= 57));
}


function esDigito(sChr){
	var sCod = sChr.charCodeAt(0);
	return ((sCod > 47) && (sCod < 58));
}

function valSep(vTxt){
	var bOk = false;
	bOk = bOk || ((vTxt.charAt(2) == "-") && (vTxt.charAt(5) == "-"));
	bOk = bOk || ((vTxt.charAt(2) == "/") && (vTxt.charAt(5) == "/"));
	return bOk;
}

function finMes(vTxt){
	var nMes = parseInt(vTxt.substr(3, 2), 10);
	var nRes = 0;
	
	switch (nMes){
		case 1: nRes = 31; break;
		case 2: nRes = 29; 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;
}

function valDia(vTxt){
	var bOk = false;
	var nDia = parseInt(vTxt.substr(0, 2), 10);
	bOk = bOk || ((nDia >= 1) && (nDia <= finMes(vTxt)));
	return bOk;
}

function valMes(vTxt){
	var bOk = false;
	var nMes = parseInt(vTxt.substr(3, 2), 10);
	bOk = bOk || ((nMes >= 1) && (nMes <= 12));
	return bOk;
}

function valAno(vTxt){
	var bOk = true;
	var nAno = vTxt.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 valFecha(vTxt, idTxt){
function valFecha(idTxt){
	vTxt = $('#' + idTxt).val();
	var bOk = true;
	
	if (vTxt != ""){
		bOk = bOk && (valAno(vTxt));
		bOk = bOk && (valMes(vTxt));
		bOk = bOk && (valDia(vTxt));
		bOk = bOk && (valSep(vTxt));
		
		if (!bOk){
			setStyleError(idTxt);
			return false;
		} else {
			setStyleOk(idTxt);
			return true;
		}
	}
}

//function checkMail(vTxt, idTxt){
function checkMail(idTxt){
	vTxt = $('#' + idTxt).val();
	
	if (/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(vTxt)){
		setStyleOk(idTxt);
		return true;
	} else {
		setStyleError(idTxt);
		return false;
	}
}

function setStyleError(idTxt) {
	$('#' + idTxt).css({ color: "#FF0000", background: "#FFFF66", border: "1px solid #FF0000" });	
	$('#' + idTxt).focus();
}

function setStyleOk(idTxt) {
	$('#' + idTxt).css({ color: "#000000", background: "#FFFFFF", border: "1px solid #666666"});	
}