提交表单执行js 问题

这是我需要提交的页面<HTML><HEAD><TITLE>职位管理</TITLE>
<SCRIPT language=JavaScript>
function SelectAllItem(item)
{
    if( typeof(item.length) == "undefined" )
    {
        item.checked = !item.checked
    }
    else
    {
        for(i=0;i<item.length;i++)
        {
            item[i].checked=!item[i].checked
        }
    }
}<SCRIPT language=JavaScript>
function allcheckbox() 
{ 
   
　
if ( !form3.ncid.length ) // 只有一个复选框，form3.checkbox1.length = undefined 
　{ 
　　if ( form3.ncid.checked ) 
　　　form3.allcheckboxs.value = form3.ncid.value; 
　} 
　else 
　{ 
　　for ( i = 0 ; i < form3.ncid.length ; i++ ) 
　　{ 
　　　if ( form3.ncid(i).checked ) // 复选框中有选中的框 
　　　{ 
　　　　form3.allcheckboxs.value = form3.ncid(i).value; 
　　　　for ( j = i + 1 ; j < form3.ncid.length ; j++ ) 
　　　　{ 
　　　　　if ( form3.ncid(j).checked ) 
　　　　　{ 
　　　　　　form3.allcheckboxs.value += ","; //用,做分割符 
　　　　　　form3.allcheckboxs.value += form3.ncid(j).value; 
　　　　　} 
　　　　} 
　　　　break; 
　　　} 
　　} 
　} 
　return true; 
}  </SCRIPT>
<bodyleftMargin=0 topMargin=0>
<? include "head.php"?>
<TABLE cellSpacing=0 cellPadding=0 width=768 align=center bgColor=#ffffff 
border=0>
  <Tbody>
  <TR>
    <TD>
      <TABLE cellSpacing=0 cellPadding=0 width=760 align=center border=0>
        <Tbody>
        <TR>
          <TD height=4></TD></TR></TBODY></TABLE>
      <TABLE cellSpacing=0 cellPadding=0 width=760 align=center border=0>
        <Tbody>
        <TR>
          <TD vAlign=top width=175>
            <? include "publishleft.php"?>
</TD>
          <TD width=5>&nbsp;</TD>
          <TD vAlign=top>
  <form name="form3" id="form3" action="Com_JobOption.php" method="post" onSubmit="return allcheckbox();" >
            <TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
              
              <Tbody>
              <TR>
                <TD>
                  <TABLE cellSpacing=1 cellPadding=0 width="100%" 
                  bgColor=#eeeeee border=0>
                    <Tbody>
                    <TR>
                      <TD bgColor=#ffffff>
                        <TABLE cellSpacing=0 cellPadding=0 width="99%" 
                        align=center border=0>
                          <Tbody>
                          <TR>
                            <TD height=2></TD></TR></TBODY></TABLE>
                        <TABLE cellSpacing=1 cellPadding=0 width="99%" 
                        align=center bgColor=#eeeeee border=0>
                          <Tbody>
                          <TR>
                            <TD bgColor=#f5f5f5 height=25><B><FONT 
                              color=#000000>&nbsp;职位管理</FONT></B></TD></TR></TBODY></TABLE>
                        <TABLE cellSpacing=0 cellPadding=0 width="99%" 
                        align=center border=0>
                          <Tbody>
                          <TR>
                            <TD>
                              <TABLE class=text01 cellSpacing=1 cellPadding=0 
                              width="100%" border=0>
                                <Tbody>
                                <TR>
                                <TD width="50%">共有2条记录 | 分1页显示</TD>
                                <TD align=right><FONT color=#666666>首页</FONT> 
                                <FONT color=#666666>上页</FONT> &lt;1&gt; <FONT 
                                color=#666666>下页</FONT> <FONT 
                                color=#666666>尾页</FONT> 
                            </TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
                        <TABLE cellSpacing=1 cellPadding=2 width="99%" 
                        align=center bgColor=#eeeeee border=0>

                          <Tbody>
  
                          <TR align=middle bgColor=#f5f5f5>
                            <TD width="7%" height=23>编号</TD>
                            <TD width="23%" bgColor=#f5f5f5 height=23>招聘职位</TD>
                            <TD width="10%" bgColor=#f5f5f5 height=23>状 态</TD>
                            <TD width="12%" bgColor=#f5f5f5 height=23>浏览/应聘</TD>
                            <TD width="25%" bgColor=#f5f5f5 
height=23>招聘起止日期</TD>
                            <TD height=23>单项操作</TD>
                            <TD width="6%" height=23>选择</TD></TR>

<? 

$numrows = mysql_num_rows($result);
$total=0;
if($numrows>0)
{
while($data = mysql_fetch_array($result))
{

$total+=1;

?>


                          <TR align=middle>
                            <TD bgColor=#ffffff height=23><? echo $total ?></TD>
                            <TD align=left bgColor=#ffffff height=23><A 
                              href="Info/Com_JobView.php?Param=<? echo $data["id"]?>" 
                              target=_blank><? echo $data["job_name"]?></A></TD>
                            <TD bgColor=#ffffff height=23>

<? 
if ($data["job_hide"]==0)
{
echo "招聘中";
}
else
{

echo "已经屏蔽";
}
?> 
</TD>
                            <TD bgColor=#ffffff height=23><? echo $data["readed_numbers"]?>/<? echo $data["apply_numbers"]?></TD>
                            <TD bgColor=#ffffff 
height=23><? echo date("Y-m-d")?>-<? echo substr($data["end_date"],0,10)?></TD>
                            <TD bgColor=#ffffff height=23><A 
                              href="Com_JobEdit.php?Param=<? echo $data["id"]?>">编辑</A>|<A 
                              href="Com_JobCopy.php?Param=<? echo $data["id"]?>">复制</A>|<A 
                              href="../Person/Per_Search_Jobauto.php?Param=<? echo $data["id"]?>" 
                              target=_blank>匹配</A></TD>
  
                            <TD bgColor=#ffffff height=23>
<input type="checkbox" name="ncid"
                              value="<? echo $data["id"]?>"> 
  </TD>
   
   
  </TR>
  <?
  
  }

}
  ?>

  </TBODY>
  
  </TABLE>
                        <TABLE cellSpacing=0 cellPadding=0 width="99%" 
                        align=center border=0>
                          <Tbody>
                          <TR>
                            <TD align=right>
   <input name="allcheckboxs" type="hidden" value=""> 
<INPUT 
                              onclick=SelectAllItem(this.form.ncid) 
                              type=checkbox value=all name=chk_all> 选中所有招聘职位 
                          </TD></TR></TBODY></TABLE>
                        <TABLE cellSpacing=0 cellPadding=0 width="99%" 
                        align=center border=0>
                          <Tbody>
                          <TR>
                            <TD 
                  height=2>

  </TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE></TD></TR>
              <TR>
                <TD align="center" height=40>
<input type="submit" name="Submit4" value="Submit4"> 
                </TD></TR></TBODY></TABLE>

</FORM>
            </BODY></HTML>
//////////////////
这是我需要处理提交的页面
<?
session_start();
include "../harcconfig/config.inc.php";
$company_dataid=$_SESSION["company_dataid"];
mysql_query("set names gb2312");
$a=$_POST["allcheckboxs"];
echo $a;
exit;?><html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
</head><body>
</body>
</html>
/////////////////////////////////////
因为实际上没有执行allcheckbox 函数,所以获得checkbox的值为空,所以许多操作都没有办法执行,现在很着急,非常希望能够有高手帮我看下是什么原因,非常感谢