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("Email address seems incorrect (check @ and .'s)")
                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){alert("Destination IP address is invalid!")
                return false}}return true}var domainArray=domain.match(domainPat)
		if(domainArray==null){alert("The domain name doesn't seem to be 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("The address must end in a three-letter domain, or two letter country.")
                return false}if(len<2){var errStr="This address is missing a hostname!"
                alert(errStr)
                return false}return true;
        }