关于javascript里面提取select的value值的问题

<SCRIPT language=JavaScript>
<!--
function processForm(form){
var xf=0;
if (form.c2[0].value=="1") form.answer.value=xf+2000;
if (form.c2[1].value=="2") form.answer.value=xf+1500;
if (form.c2[2].value=="3") form.answer.value=xf+1000;
}
//-->
</SCRIPT>
<form name="form">
<select name="c2">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<INPUT onclick=processForm(this.form) style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt" type=button value=都选择完了，结果怎样?>
<textarea name="answer" cols="" rows=""></textarea>
</form>

也就是选择select里面的不同value值

然后通过上面那个js显示不同的xf的值到textarea里面

可是那个js总有问题

请问怎么写才正确

<SCRIPT language=JavaScript>
<!--
function processForm(form){
var xf=0;
if (form.c2.value=="1") form.answer.value=xf+2000;
if (form.c2.value=="2") form.answer.value=xf+1500;
if (form.c2.value=="3") form.answer.value=xf+1000;
}
//-->
</SCRIPT>
<form name="form" ID="Form1">
<select name="c2" ID="Select1">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<INPUT onclick=processForm(this.form) style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt" type=button value=都选择完了，结果怎样? ID="Button1" NAME="Button1">
<textarea name="answer" cols="" rows="" ID="Textarea1"></textarea>
</form>