test evaluare html

Salut!
Dupa cum cred ca vati dat seama incerc sa fac un test de evaluare in html. Codurile le-am facut tot.. imi calculeaza bine dar care e problema... in momentul in care se selecteaza un raspuns acesta nu ramane validat, adik pot sa aleg altul.. si asa se poate obstine punctaj mare foarte usor.. mai joc este codul pe care il foslosesc.. cine ma poate ajuta raman dator..

<form id="form3" action="" method="get">

Intrebare 1
<br>
Raspunsuri:
<br>
<input type="radio" name="item" value="A" />A
<br>
<input type="radio" name="item" value="B" />B
<br>
<input type="radio" name="item" value="C" />C
<br>
<hr>
Intrebare 2
<br>
Raspunsuri:
<br>
<input type="radio" name="item2" value="D" />A
<br>
<input type="radio" name="item2" value="E" />B
<br>
<input type="radio" name="item2" value="F" />C
<br>

<hr>
Intrebare 3
<br>
Raspunsuri:
<br>
<input type="radio" name="item3" value="G" />A
<br>
<input type="radio" name="item3" value="H" />B
<br>
<input type="radio" name="item3" value="I" />C
<br>
<br>
<input type="button" id="submit" value="Calculeaza punctaj" onclick="processForm()" />
<br>
Punctajul tau <input type="text" id="total" size="10" maxlength="10" readonly="readonly" value="0" />

</form>

<script type="text/javascript">
function processForm() {
//get form variables
var theItems = document.getElementsByName( "item" );
var theItems2 = document.getElementsByName( "item2" );
var theItems3 = document.getElementsByName( "item3" );

var pctOficiu = 1.00;

var selectedItem;
var selectedItem2;
var selectedItem3;
var orderTotal = 0.00;
var orderTotal1;
var orderTotal2;
var orderTotal3;
var outBox = document.getElementById( "total" );

for(var i = 0; i < theItems.length; i++) {
if( theItems[i].checked) {
selectedItem = theItems[i].value;
break;
}
}

switch(selectedItem) {
case "A":
total1 = 4.00;
break;
case "B":
total1 = 0.00;
break;
case "C":
total1 = 0.00;
break;
default:
total1 = 0.00;
}

for(var i = 0; i < theItems2.length; i++) {
if( theItems2[i].checked) {
selectedItem2 = theItems2[i].value;
break;
}
}

switch(selectedItem2) {
case "D":
total2 = 0.00;
break;
case "E":
total2 = 2.00;
break;
case "F":
total2 = 0.00;
break;
default:
total2 = 0.00;
}

for(var i = 0; i < theItems3.length; i++) {
if( theItems3[i].checked) {
selectedItem3 = theItems3[i].value;
break;
}
}

switch(selectedItem3) {
case "G":
total3 = 3.00;
break;
case "H":
total3 = 0.00;
break;
case "I":
total3 = 0.00;
break;
default:
total3 = 0.00;
}


total = total1 + total2 +total3 + pctOficiu;

outBox.value = total.toString();
}
</script>