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("Wrong email!")
	return false
}
var user=matchArray[1]
var domain=matchArray[2]

// See if "user" is valid 
if (user.match(userPat)==null) {
    // user is not valid
    alert("Wrong name!.")
    return false
}


var IPArray=domain.match(ipDomainPat)
if (IPArray!=null) {
	  for (var i=1;i<=4;i++) {
	    if (IPArray[i]>255) {
	        alert("Ip is bad!")
		return false
	    }
    }
    return true
}


var domainArray=domain.match(domainPat)
if (domainArray==null) {
	alert("Domain is bad.")
    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("Address have to contain domain.")
   return false
}

if (len<2) {
   var errStr="Adresa nemá hostitele"
   alert(errStr)
   return false
}

var jmeno = document.forms.emailform.jmeno;
if (jmeno.value == "") {
	alert("First name and last name is missed");
	return false;
}
var captcha = document.forms.emailform.captcha;
if (captcha.value == "") {
	alert("Missed check code");
	return false;
}
var text = document.forms.emailform.text;
if (text.value == "") {
	alert("Missed body message");
	return false;
}

return true;
}