var CorrectAnswer=document.all(correct+i);
or
var CorrectAnswer=eval(correct+i);
etc.

解决方案 »

  1.   

    var CorrectAnswer=correct+i;
    改为
    var CorrectAnswer=document.all("correct"+i)
      

  2.   

    <body>
    <span id=correct1 style="display:none">eqwe</span>
    <span id=correct2 style="display:none">eqwe</span>
    <span id=correct3 style="display:none">eqw</span>
    <script language=javascript>
    function answer()//显示正确答案
    {

    var correct="correct";
    for (i=1;i<3;i++)
    {
    var CorrectAnswer=correct+i;
    if (document.getElementById(CorrectAnswer).style.display=='none')
    document.getElementById(CorrectAnswer).style.display='';
    }
    }
    answer();
    </script>
    </body>
      

  3.   

    function answer(type)//显示正确答案
    {

    var correct="correct";
    for (i=1;i<3;i++)
    {
    var CorrectAnswer=correct+i;
    if (eval(CorrectAnswer.style.display=='none'))
    eval(CorrectAnswer.style.display='');
    }
    }<span id=correct1 style="display:none">eqwe</span>
    <span id=correct2 style="display:none">eqwe</span>
    <span id=correct3 style="display:none">eqw</span>
      

  4.   

    如果你的元素是有id属性的话还是用document.getElementById("idName")这样的方法获得元素的参考比较好!function answer(type)//显示正确答案
    {

    var correct="correct";
    for (i=1;i<3;i++)
    {
    var CorrectAnswer=document.getElementById(correct+i);
    if (CorrectAnswer.style.display=='none')
    CorrectAnswer.style.display='';
    }
    }<span id=correct1 style="display:none">eqwe</span>
    <span id=correct2 style="display:none">eqwe</span>
    <span id=correct3 style="display:none">eqw</span>