php解决checkbox问题

<script language="javascript" type="text/javascript">
function checkbox()
{
var str=document.getElementsByName("chk");
var objarray=str.length;
var chestr="";
for (i=0;i<objarray;i++)
{
if(str[i].checked == true)
{
chestr+="1";
} else{
chestr+="0";
}
}
document.getElementById("txtcheck").value=chestr;
}
</script>
<tr>
                           <td colspan="4"><table width="100%" border="0" cellspacing="0" cellpadding="0">
                               <tr>
                                 <td width="4%" height="25" align="left"><input type="checkbox" value="c1" name="chk" /></td>
                                 <td width="12%" align="left">动力转向</td>
                                 <td width="5%" align="left"><input type="checkbox" value="c2" name="chk" /></td>
                                 <td width="7%" align="left">ABS</td>
               &n