<script>
function getMailAdd()
{
 for(i=0;i<document.all.r_email.length;i++)
 {
  if(document.all.r_email[i].checked)
  {
   document.all.email.action="mailto:"+document.all.r_email[i].value;
  }
 }}
</script>
<table width="640" height="20" border="0" cellpadding="0" cellspacing="0"> 
<form action="mailto:[email protected]" enctype="multipart/form-data" name="email" id="email" onsubmit="getMailAdd()"> 
<tr> 
<td width="98" class="url_main">姓名</td> 
<td width="515"><input name="username" type="text" id="username"></td> 
</tr> 
<tr> 
<td class="url_main">邮件</td> 
<td><input name="r_email" type="radio" value="[email protected]" checked>1 
<input name="r_email" type="radio" value="[email protected]">2 
<input name="r_email" type="radio" value="[email protected]">3 
<input name="r_email" type="radio" value="[email protected]">4 
</td> 
</tr> 
<tr> 
<td colspan="2"><input type="submit" name="Submit" value="Submit"></td> 
</tr> 
</form> 
</table> 请问红字部分有何意义?不是radio控件选择后使得document.all.email.action="mailto:"+document.all.r_email[i].value;么?