function isStringValid( string ) {
    for( var i=0; i<string.length; i++ ) {
        if( string.charAt(i)!=" " ) {
            return 1;
        }
    }
    return 0;
}
function onSubmitFeedback( form ) {
    if( !isStringValid(form.feedback.value) ) {
        alert("Please type your comments first");
    }
    else {
        form.submit();
    }
}