function checkEmail(emailStr) {

	var checkTLD 		= 1;

	var knownDomsPat	= /^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
	var emailPat		= /^(.+)@(.+)$/;
	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);
	var done			= true;
	var	err				= "";

	if (matchArray == null) {
		err 	= "Email address seems incorrect";
		done	= false;
	}
	
	if(done){
		var user	= matchArray[1];
		var domain	= matchArray[2];

		for (i=0; i<user.length; i++) {
			if (user.charCodeAt(i)>127) {
				err 	= "This username contains invalid characters";
				done	= false;
			}
		}
	}

	if(done){
		for (i=0; i<domain.length; i++) {
			if (domain.charCodeAt(i)>127) {
				err 	= "This domain name contains invalid characters";
				done	= false;
			}
		}
	}

	if(done){
		if (user.match(userPat)==null) {
			err 	= "The username doesn't seem to be valid";
			done	= false;
		}
	}
	
	if(done){
		var IPArray = domain.match(ipDomainPat);

		if (IPArray!=null) {
			for (var i=1;i<=4;i++) {
				if (IPArray[i]>255) {
					err 	= "Invalid email address";
					done	= false;
	   			}
			}
		}
	}


	if(done){
		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) {
				err 	= "Invalid email address";
				done	= false;
	   		}
		}
	}

	if(done){
		if (checkTLD && domArr[domArr.length-1].length!=2 && domArr[domArr.length-1].search(knownDomsPat)==-1) {
			err 	= "Invalid email address";
			done	= false;
		}
	}

	if(done){
		if (len<2) {
			err 	= "Invalid email address";
			done	= false;
		}
	}

	return err;
}