PHP AJAX MySQL DELETE not working

我使用的是Javascript（而不是JQuery）。我正在尝试从MySQL数据库中删除使用复选框选中的记录。使用AJAX不会进行删除。然而，如果我使用相同的参数手动调用PHPAJAX删除脚本，删除操作会很好。然而，当我手动运行AJAX PHP时，即使所有内容都在同一服务器和同一域上，我的Firefox浏览器也会报告COR。

以下是HTML、Javascript和AJAX PHP删除脚本：

如果重要的话，这个html在iframe中：

<form name='frmDelFiles' method='POST' class='frmFileUpload' onClick='delChkdFiles("files2del")'>
<input type='submit' value='Delete Checked Files' name='delFiles' class='btnSubmit' />
</form>

Javascript：

function delChkdFiles(theCBgrp) {
    var where_stmt = "";
    var names      = "";
    var elements = document.getElementsByName(theCBgrp);
   for (var i = 0, l = elements.length; i < l; i++)
   {
      if (elements[i].checked)
      {
        var response = confirm("Do you consent to delete the " + elements[i].value + " file?'n'nClick OK if Yes, otherwise Cancel.");
        if (response == true) {
            if (where_stmt == "") {
                where_stmt  = "id=" + elements[i].id;
                names       = elements[i].value;
            } else {
                   where_stmt += " OR id=" + elements[i].id;
                   names      += ", " + elements[i].value;
                }
        }
    }
    }
    if (where_stmt == "") {
        alert("Zero files have been selected for deletion.");
    } else {
        xmlhttp=getHTTPObject();
       if (xmlhttp==null) {
            alert ("Your browser does not support AJAX!");
            return;
       }
        var url="/php/del_mysql_rcd.php";
        url=url+"?table=ip_attachments";
        url=url+"&where_stmt="+where_stmt;
        url=url+"&names="+names;
        url=url+"&sid="+Math.random();
        xmlhttp.open("GET",url,true);
        xmlhttp.onreadystatechange = handleShowResponse;
        xmlhttp.send(null);
    }
}
function handleShowResponse() {
   if (xmlhttp.readyState==4) {
      var ajaxStr = xmlhttp.responseText;
      alert(ajaxStr);
   }
}

del_mysql_rcd.php AJAX php:

<?php
$table      = $_GET["table"];
$where_stmt = $_GET["where_stmt"];
$names      = $_GET["names"];
require_once ('../php/mysql_connect.php'); // Connect to the db.
$query = "DELETE FROM $table WHERE $where_stmt";
$result = @mysql_query ($query) or die(mysql_error()); // Run the query.
if (mysql_affected_rows() > 0) {
    echo "Successfully deleted $names'n";
} else {
    echo "Failed to delete $names'n";
}
?>