js的表单网页调用问题 小程序帮帮调试

<form type="text" name="newnumber" method="post">
<p>
<input type="text" name="user1"/>数学
</p>
<p><br/>
<input type="text" name="user2"/>语文
</p>
<p> <br/>
<input type="text" name="user3"/>英语

</p>
<script language="javascript"> answer1=eval("document.newnumber.sub.user1+document.newnumber.sub.user2+document.newnumber.sub.user3")</script>
<input type="submit" name="sub" value="提交"
onclick="javascript:alert('answer is'+answer1)"/>
<form>

警告显示的结果是 answer is 然后就没了
我的

<form type="text" name="newnumber" method="post">
<p>
<input type="text" name="user1" id="user1"/>数学
</p>
<p><br/>
<input type="text" name="user2" id="user2"/>语文
</p>
<p> <br/>
<input type="text" name="user3" id="user3"/>英语

</p>
<script language="javascript">
function $(id)
{
return document.getElementById(id);
}
function evals(){
answer1=parseInt($("user1").value)+parseInt($("user2").value)+parseInt($("user3").value)
alert('answer is'+' '+answer1)
}
</script>
<input type="submit" name="sub" value="提交"
onclick="evals()"/>
</form>