怎么用脚本弹出一个RadionButtonList的各个选项的Text


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>RadioButtonListText</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body MS_POSITIONING="GridLayout">
<form name="Form1" method="post" action="RadioButtonListText.aspx" id="Form1">
<input type="hidden" name="__VIEWSTATE" value="dDwtMTQ2MTEwNDc7Oz5FWlfD7/18J3fhCTstDB28V2NE9Q==" /> <table id="RadioButtonList1" border="0" style="height:168px;width:168px;Z-INDEX: 101; LEFT: 248px; POSITION: absolute; TOP: 232px">
<tr>
<td><input id="RadioButtonList1_0" type="radio" name="RadioButtonList1" value="1" /><label for="RadioButtonList1_0">text1</label></td>
</tr><tr>
<td><input id="RadioButtonList1_1" type="radio" name="RadioButtonList1" value="2" /><label for="RadioButtonList1_1">text2</label></td>
</tr><tr>
<td><input id="RadioButtonList1_2" type="radio" name="RadioButtonList1" value="3" /><label for="RadioButtonList1_2">text3</label></td>
</tr>
</table>
<input  type=button value="ceshi " onclick="showtext();">
</form>
</body>
</HTML>
<script language=javascript>
function showtext()
{//document.getElementsByTagName
var rbList=document.getElementById('RadioButtonList1');
var radios=rbList.getElementsByTagName("INPUT");
var strText='';
for(var i=radios.length-1;i>=0;i--)
{
    strText+=radios[i].innerText;
}
alert(strText);
}
</script>