function validateForm(form){
    var validator = new Validator();
    var field = form.elements["txtEmail"];
    var errMsg = "This field is required";
    if (validator.isEmpty(field.value)){
        validator.indicateError(field, errMsg);
        return false;
    }
    else if (!validator.isEmail(field.value)){
        validator.indicateError(field, "This is not valid e-mail address");
        return false;
    }
    else{
        validator.clearError(field);
    }
    field = form.elements["txtSubject"];
    if (validator.isEmpty(field.value)){
        validator.indicateError(field, errMsg);
        return false;
    }
    else{
        validator.clearError(field);
    }
    field = form.elements["txtMessage"];
    if (validator.isEmpty(field.value)){
        validator.indicateError(field, errMsg);
        return false;
    }
    else{
        validator.clearError(field);
    }
    field = form.elements["txtCaptcha"];
    if (validator.isEmpty(field.value)){
        validator.indicateError(field, errMsg);
        return false;
    }
    else{
        validator.clearError(field);
    }
    return true;
}