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); 
}