请问如何取得getElementsByName("spna")的值？？？？？？

[cheng17]

getElementsByName("spid"),getElementsByName("spna")这两个应该如何取啊？allnum是form1的一个隐藏变量
function Deldel()
{
var spid,spna;
var allnum;
allnum=eval(form1.allnum.value) + 1;
spid="spid" + allnum;
spna="spna" + allnum;

var txt1 = document.getElementsByName("spid");
if(txt1.length)
{txt1[txt1.length-1].removeNode(true);
}
var txt2 = document.getElementsByName("spna");
if(txt2.length)
{txt2[txt2.length-1].removeNode(true);
}
}

[littleboys]

<FORM METHOD=POST ACTION="">
<INPUT TYPE="text" NAME="spid2" value="aaa">
</FORM>
</BODY>
</HTML>
<SCRIPT LANGUAGE="JavaScript">
<!--
var spid="spid" + "2";

var txt1 = document.getElementsByName(spid)[0].value;
alert(txt1);
//-->
</SCRIPT>

[shyslysky]

if(txt1.length) // if(txt1.length>0)
{txt1[txt1.length-1].removeNode(true);
}