function wrapto(t, n)
{
	if (t.value.length>n)	t.value=t.value.substr(0,n);
}
function esDominio(d)
{
	if (d.length!=6) return false;
	for(i=0;i<3 && isAlpha(d.charAt(i));i++);
	return i==3 && isInteger(d.substr(3,6));
}
function isAlpha(c)
{
	return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
}
function isInteger(n)
{
	inputStr = n.toString()
	for (var i = 0; i < inputStr.length; i++)
	{
		var oneChar = inputStr.charAt(i)			
		if (oneChar < "0" || oneChar > "9") return false;
	}
	return true;
}
function emailCheck (emailStr) 
{
var emailPat=/^(.+)@(.+)$/
var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
var validChars="\[^\\s" + specialChars + "\]"
var quotedUser="(\"[^\"]*\")"
var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
var atom=validChars + '+'
var word="(" + atom + "|" + quotedUser + ")"
var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")
var matchArray=emailStr.match(emailPat)
if (matchArray==null) {
	alert("Dirección de email incorrecta.")
	return false
}
var user=matchArray[1]
var domain=matchArray[2]

if (user.match(userPat)==null) {
    alert("Dirección de email incorrecta.")
    return false
}
var IPArray=domain.match(ipDomainPat)
if (IPArray!=null) {
	  for (var i=1;i<=4;i++) {
	    if (IPArray[i]>255) {
	        alert("Dirección de email incorrecta.")
		return false
	    }
    }
    return true
}

var domainArray=domain.match(domainPat)
if (domainArray==null) {
	alert("Dirección de email incorrecta.")
    return false
}

var atomPat=new RegExp(atom,"g")
var domArr=domain.match(atomPat)
var len=domArr.length
if (domArr[domArr.length-1].length<2 || 
    domArr[domArr.length-1].length>3) {
   alert("Dirección de email incorrecta.")
   return false
}

if (len<2) {
   var errStr="Dirección de email incorrecta."
   alert(errStr)
   return false
}

return true;
}