function isValidEmail(email) {
   
    
    	if (email.length==0){  
        	return false;
    	}
    	if (! allValidChars(email)){                                   // check to make sure all characters are valid
        	return false;
    	}
    	if (email.indexOf("@") < 1){                                   //  must contain @, and it must not be the first character
        	return false;
    	} else if (email.lastIndexOf(".") <= email.indexOf("@")){      // last dot must be after the @
        	return false;
    	} else if (email.lastIndexOf("@") == email.length){            // @ must not be the last character
        	return false;
	} else if (email.lastIndexOf('.') == email.length){            // . must not be the last character
                return false;
    	//} else if (email.indexOf("..") >=0){                         // two periods in a row is not valid
		//return false;
    	} else if (email.indexOf("@") != email.lastIndexOf("@") ){     // Only 1 @ is alowed
        	return false;
    	}
	//alert( "last: " + email );
    	return true;
}

function allValidChars(email) {
	var parsed = true;
	var validchars = "abcdefghijklmnopqrstuvwxyz0123456789@.-_";
	for (var i=0; i < email.length; i++) {
    		var letter = email.charAt(i).toLowerCase();
    		if (validchars.indexOf(letter) != -1){
      			continue;
		}
    		parsed = false;
    		break;
  	}
  	return parsed;
}