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)
		return false
	var user=matchArray[1]
	var domain=matchArray[2]

	if (user.match(userPat)==null)
	{
	    alert("The username doesn't seem to be valid.")
	    return false
	}

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

	var domainArray=domain.match(domainPat)
	if (domainArray==null)
    	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>4)
	   return false

	if (len<2)
		return false

	return true;
}