单选试题 答案保存 调用另一个function

当点击下一题跳转页面,第五次时没有变为提交,且无法触发score方法,同时没选一题答案,跳转页面时如何存储

<SCRIPT LANGUAGE="JavaScript">
function Engine(question, answer) {
yourAns[question]=answer;
}
<!-- Begin
function Score(){
var answerText = "看看你的成绩如何?\n------------------------------------\n";
for(i=1;i<=5;i++){
ans[i]=s;
answerText=answerText+"\n问题:"+i+"\n";
if(ans[i]!=yourAns[i]){
answerText=answerText+"\n正确的答案是: "+ans[i]+"\n";
}
else{
answerText=answerText+" \n对的 \n";
score++;
}
}
answerText=answerText+"\n\n你的成绩是 : "+score+"\n";
//now score the user
alert(answerText);

}
// End -->
</script>
<script>
var index=1;
function f1(obj){
if(obj.value=="下一题"){
window.location.href="1.asp";
}
}
function f2(obj){
if(obj.value=="下一题"){
window.location.href="1.asp";
}
}


function f3(obj){
if(obj.value=="下一题"){
window.location.href="1.asp";
}
}
function f4(obj) {
   if (document.form1.obj.value=="下一题")
   {
     document.form1.obj.value="提交";
   }

  window.location.href="1.asp";
}

function f5(){
if(document.form1.obj.value=="提交"){
obj.onclick=score();
}
}


function test(obj){
  if (index>5){//防止超出
  index=1;
}
  eval('f'+index+'();');
 index++;
}


</script>
<body>
    <form id="form1" name="form1" method="post" action="">

      <p>
        <label>
          <input type="radio" name="RadioGroup1" value="1" id="RadioGroup1_0" onClick="Engine(2, this.value)"/>
          p1</label>

        <label>
          <input type="radio" name="RadioGroup1" value="2" id="RadioGroup1_1" onClick="Engine(2, this.value)"/>
          p2</label>

          </p>

    </form>

 <form name="form1" method="post" action="">
<input name="obj" type="submit" id="obj" value="下一题" onClick="test(this);">
</form>

</body>

你明明提交的是asp,应该在第四次的时候asp输出的时候,改掉obj的value,用js改的结果就是经过asp后被刷掉了

eval('f'+index+'();')这句执行f1,f2,f3时报错了,if(obj.value=="下一题"){中的obj是null