function testLetter(form){
inpVal = form.entry.value;
if (inpVal != "") {
if (inpVal == "A") {
alert("Thanks for the A.");
} else if (inpVal == "B") {
alert("Thanks for the B.");
} else if (inpVal == "C") {
alert("Thanks for the C.");
} else {
alert("Sorry, wrong letter or case.")
}
} else {
alert("You did not enter anything.")
}
}