javascript脚本编程解决考试分数统计问题

/**
* @author georgewing
*/
function prepareCheckBox() {
document.getElementById("submit").onclick = function() {
selectedCheckBox(4);
}
}
function selectedCheckBox(x) {
var oInput = document.getElementsByTagName("input");
var iTotal = 0;
for(var i=0;i<oInput.length;i++) {
if(oInput[i].className == "checkedRadio") {
if(oInput[i].checked) {
//add x point
iTotal = iTotal + x;
}
else {
// add 0 point
iTotal = iTotal + 0;
}
}

}
document.getElementById("Total").setAttribute("value", iTotal);
alert(iTotal);
}