数学计算游戏

下面为效果显示



剩余时间:
题目:
在这里写答案:
得分:

脚本说明:
把如下代码加入<body>区域中
<SCRIPT LANGUAGE="JavaScript">

function startgame()
{if (started!=0)
{alert('你已经开始了');}
else
{
started=1;
CountDown();
getProb();
}
}

function randnum(min,max)
{
var num=Math.round(Math.random()*(max-min))+min;
return num;
}

var choose, rightanswer
function getProb()
{
choose=randnum(1,4);
if (choose=="1")
{document.math.operator.value="+";
var choose1=randnum(0,50);
var choose2=randnum(0,50);
document.math.firstnum.value=choose1;
document.math.secondnum.value=choose2;
rightanswer=choose1 + choose2;
}
if (choose=="2")
{document.math.operator.value="-";
var choose2=randnum(0,50);
var choose1=randnum(choose2,50);
document.math.firstnum.value=choose1;
document.math.secondnum.value=choose2;
rightanswer=choose1 -  choose2;
}
if (choose=="3")
{document.math.operator.value="x";
var choose1=randnum(0,10);
var choose2=randnum(0,10);
document.math.firstnum.value=choose1;
document.math.secondnum.value=choose2;
rightanswer=choose1 * choose2;
}
if (choose=="4")
{document.math.operator.value="/";
var choose2=randnum(1,10);
var choose1=choose2 * randnum(0,10);
document.math.firstnum.value=choose1;
document.math.secondnum.value=choose2;
rightanswer=choose1 /  choose2;
}
}
function answerit()
{
if (started==0)
{alert('你必须先点击开始');}
else
{
if (timesup!=0)
{alert('你超时!');}
else
{
var theiranswer=eval(document.math.answer.value);
var theirpoints=eval(document.math.points.value);
if (theiranswer==null)
{alert('请在正确的地方输入答案');
document.math.answer.select();}
else
{
if (theiranswer==rightanswer)
{
alert('正确');
theirpoints++;
document.math.points.value=theirpoints;
}
else
{alert(theiranswer + " 错了!\n\n"+rightanswer + " 是正确的答案!")}
document.math.answer.select();
getProb();
}
}
}
}
//  End -->
</script>
<table align="left">
  <tr>
    <td colspan="3" align="center"><input type="button" value="新游戏" onClick="location.reload();"></td></tr><tr>
    <td colspan="3" align="center"><input type="button" value="开始" size="5" onClick="startgame()"></td>
  </tr>
  <tr>
    <form name="math">
      <td colspan="3" align="center"><font face="Arial, Helvetica, Sans Serif" size="3" color="#0000FF"><b>剩余时间:</b> </font><input type="text" name="timer" size="5"></td>
    </tr>
    <tr>
      <td align="right"><font face="Arial, Helvetica, Sans Serif" size="3" color="#0000FF"><b>题目:</b> </font><input type="text" name="firstnum" size="5"></td>
      <td align="center"><input type="text" name="operator" size="2"></td>
      <td align="left"><input type="text" name="secondnum" size="5"></td>
    </tr>
    <tr>
      <td colspan="3" align="center"><hr><font face="Arial, Helvetica, Sans Serif" size="3" color="#0000FF"><b>在这里写答案:</b></font> <input type="text" name="answer" size="5"> <input type="button" value="提交答案" onClick="answerit();"><hr></td>
    </tr>
    <tr>
      <td  colspan="3" align="center"><font face="Arial, Helvetica, Sans Serif" size="3" color="#0000FF"><b>得分:</font></b> <input type="text" name="points" size="5" value="0"></td>
    </tr>
    <tr>
    </form>
  </tr>
</table>