function emailCheck(emailStr){var checkTLD=1;var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/i;var emailPat=/^(.+)@(.+)$/;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+")*$");
var matchArray=emailStr.match(emailPat);if(matchArray==null){alert("Email address seems incorrect (check @ and .'s)");return false;}
var user=matchArray[1];var domain=matchArray[2];for(i=0;i<user.length;i++){if(user.charCodeAt(i)>127){alert("Ths username contains invalid characters.");return false;}}
for(i=0;i<domain.length;i++){if(domain.charCodeAt(i)>127){alert("Ths domain name contains invalid characters.");return false;}}
if(user.match(userPat)==null){alert("The username doesn't seem to be valid.");return false;}
var IPArray=domain.match(ipDomainPat);if(IPArray!=null){for(var i=1;i<=4;i++){if(IPArray[i]>255){alert("Destination IP address is invalid!");return false;}}
return true;}
var atomPat=new RegExp("^"+atom+"$");var domArr=domain.split(".");var len=domArr.length;for(i=0;i<len;i++){if(domArr[i].search(atomPat)==-1){alert("The domain name does not seem to be valid.");return false;}}
if(checkTLD&&domArr[domArr.length-1].length!=2&&domArr[domArr.length-1].search(knownDomsPat)==-1){alert("The address must end in a well-known domain or two letter "+"country.");return false;}
if(len<2){alert("This address is missing a hostname!");return false;}//
return true;}