function isNotEmpty(elem, message){
   var str = elem.value;
   if (str == null || str.length==0){
      alert(message);
      return false;
   }
   else{
      return true;
   }
}

function isSelected(select, message){
    if (select.selectedIndex == 0){
       alert(message);
       return false;       
    }
    else{
        return true;
    }
}

function isValidEmail(elem) {
    var str = elem.value;
    str = str.toLowerCase();
    if (str.indexOf("@") > 1) {
        var addr = str.substring(0, str.indexOf("@"));
        var domain = str.substring(str.indexOf("@") + 1, str.length);
        // at least one top level domain required
        if (domain.indexOf(".") == -1) {
            alert("Verify the domain portion of the email address.");
            return false;
        }
        // parse address portion first, character by character
        for (var i = 0; i < addr.length; i++) {
            oneChar = addr.charAt(i).charCodeAt(0);
            // dot or hyphen not allowed in first position; dot in last
            if ((i == 0 && (oneChar == 45 || oneChar == 46)) ||
                (i == addr.length - 1 && oneChar == 46)) {
                alert("Verify the user name portion of the email address.");
                return false;
            }
            // acceptable characters (- . _ 0-9 a-z)
            if (oneChar == 45 || oneChar == 46 || oneChar == 95 ||
                (oneChar > 47 && oneChar < 58) || (oneChar > 96 && oneChar < 123)) {
                continue;
            } else {
                alert("Verify the user name portion of the email address.");
                return false;
            }
        }
        for (i = 0; i < domain.length; i++) {
            oneChar = domain.charAt(i).charCodeAt(0);
            if ((i == 0 && (oneChar == 45 || oneChar == 46)) ||
                ((i == domain.length - 1 || i == domain.length - 2) && oneChar == 46)) {
                alert("Verify the domain portion of the email address.");
                return false;
            }
            if (oneChar == 45 || oneChar == 46 || oneChar == 95 ||
                (oneChar > 47 && oneChar < 58) || (oneChar > 96 && oneChar < 123)) {
                continue;
            } else {
                alert("Verify the domain portion of the email address.");
                return false;
            }
        }
        return true;
    }
    alert("The email address may not be formatted correctly. Please verify.");
    return false;
}