tengo problemas con el onfocus y el onblur no se ejecutan

[Montes28]

<SCRIPT>

function startCalc(){
interval = setInterval("calc()",1);
}
function calc(){
one = document.autoSumForm.firstBox.value;
two = document.autoSumForm.secondBox.value;
document.autoSumForm.thirdBox.value = (one * 1) + (two * 1);
}
function stopCalc(){
clearInterval(interval);
}
</SCRIPT>


y creo dos inputs con php


echo"<input class='right' type='text' name='firstBox' onfocus='startCalc();' onblur='stopCalc();'readonly=''/>";

echo"<input type='text' name='secondBox' value='' onfocus='startCalc();' onblur='stopCalc();' id='secondBox'/>";

echo"<input class='right' type='text' name='thirdBox' readonly=''/>";