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("Your Email address is incorrect")
	return false
}
var user=matchArray[1]
var domain=matchArray[2]
if (user.match(userPat)==null)
{
    alert("Your Email username is not valid.")
    return false
}
var IPArray=domain.match(ipDomainPat)
if (IPArray!=null)
{
	  for (var i=1;i<=4;i++) {
	    if (IPArray[i]>255) {
	        alert("Your Email Destination IP address is invalid!")
		return false
	    }
    }
    return true
}
var domainArray=domain.match(domainPat)
if (domainArray==null)
{
	alert("Your Email domain name is not valid.")
    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("Your Email address must end in a three-letter domain, or two letter country.")
   return false
}
if (len<2)
{
   var errStr="Your Email address is missing a hostname!"
   alert(errStr)
   return false
}
return true;
}