Javascript-форум - создание теста средствами JavaScript

приведенный ниже фрагмент не работает в IE, начиная с 8

<body background="gray.jpg">

<h1>Решите примеры </h1>
<input type="button" name="b2" value="Заполнить" onclick="g()">
<form name="f1">

<br>
<table border=0>
<tr>
<td> <input type="text" name="t1" size='5'> + </td>
<td><input type="text" name="t2" size='5'></td>
<td><input type="text" name="t3" size='5'></td>
<td><input type="text" name="t4" size='5'></td>
</tr>
<tr>
<td><input type="text" name="t5" size='5'> + </td>
<td><input type="text" name="t6" size='5'></td>
<td><input type="text" name="t7" size='5'></td>
<td><input type="text" name="t8" size='5'></td>
</tr>
<tr>

<td><input type="text" name="t9" size='5'> + </td>
<td><input type="text" name="t10" size='5'></td>
<td><input type="text" name="t11" size='5'></td>
<td><input type="text" name="t12" size='5'></td>
</tr>
<tr>
<td><input type="text" name="t13" size='5'> + </td>
<td><input type="text" name="t14" size='5'></td>
<td><input type="text" name="t15" size='5'></td>
<td><input type="text" name="t16" size='5'></td>
</tr>
<tr>
<td><input type="text" name="t17" size='5'> + </td>
<td><input type="text" name="t18" size='5'></td>
<td><input type="text" name="t19" size='5'></td>
<td><input type="text" name="t20" size='5'></td>
</tr>
<tr>
<td><input type="text" name="t21" size='5'> + </td>
<td><input type="text" name="t22" size='5'></td>
<td><input type="text" name="t23" size='5'></td>
<td><input type="text" name="24" size='5'></td>
</tr>
<tr>
<td><input type="text" name="t25" size='5'> + </td>
<td><input type="text" name="t26" size='5'></td>
<td><input type="text" name="t27" size='5'></td>
<td><input type="text" name="t28" size='5'></td>
</tr>
<tr>
<td><input type="text" name="t29" size='5'> + </td>
<td><input type="text" name="t30" size='5'></td>
<td><input type="text" name="t31" size='5'></td>
<td><input type="text" name="t32" size='5'></td>
</tr>
<tr>
<td><input type="text" name="t33" size='5'> + </td>
<td><input type="text" name="t34" size='5'></td>
<td><input type="text" name="t35" size='5'></td>
<td><input type="text" name="t36" size='5'></td>
</tr>
<tr>
<td><input type="text" name="t37" size='5'> + </td>
<td><input type="text" name="t38" size='5'></td>
<td><input type="text" name="t39" size='5'></td>
<td><input type="text" name="t40" size='5'></td>
</tr>
</table>

<br>
<input type="reset" name="r1" value="Очистить" >
<br>
<input type="button" name="b1" value="Проверить" onclick="f()">
</form>

</body>
Почему?:(