我正在从数据库中获取类别及其子类别。并在使用下拉列表选择类别 bu 后过滤子类别。在我提交表单时选择后，子类别的值为0，表单不发布所选值。
<?php
if(isset($_POST) && $_POST['submit'] == "Add")
{
extract($_POST);
$scat_id = $regions['scat_id'];
echo $sqlpa = "INSERT INTO products(mcat_id, scat_id)VALUES('$mcat_id', '$scat_id')";
$resultpa = mysql_query($sqlpa);
}
?>
<script type="text/javascript">
function getregions(mcat_id) {
if (mcat_id=="") {
document.getElementById("region").innerHTML="";
return;
}
if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
} else {// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function() {
if (xmlhttp.readyState==4 && xmlhttp.status==200) {
document.getElementById("region").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","getregions.php?mcat_id="+mcat_id,true);
xmlhttp.send();
}
</script>
<form action="" method="post" name="p_add" id="p_add">
<table>
<tr>
<td>Select Category</td>
<td><select name="mcat_id" id="mcat_id" onchange="getregions(this.value);">
<option value="">Select</option>
<?php
if(!empty($resultm)) {
foreach($resultm as $rm) {
?>
<option value="<?php echo $rm['mcat_id']; ?>"><?php echo $rm['mcat_name'];?> (<?php echo $rm['mcat_id']; ?>)</option>
<?php
}
}
?>
</select>
</td>
</tr>
<tr>
<td>Select Sub-Category</td>
<td>
<div id="region">
<select name="scat_id" id="scat_id">
<option value="">Please Select</option>
</select>
</div>
</td>
</tr>
<tr>
<td> </td>
<td><input type="submit" name="submit" value="Add" /></td>
</tr>
</table>
</form>
-->这个页面是getregions.php，过滤完成的地方：
<?php
include "../conn.php";
$mcat_id=$_GET['mcat_id'];
$sql = "SELECT * FROM sub_category WHERE mcat_id = '".$mcat_id."'";
$res = mysql_query($sql);
while($row = mysql_fetch_array($res)) {
$rec[] = $row ;
}
?>
<select name="scat_id" id="scat_id">
<option value="">Please Select</option>
<?php
foreach($rec as $regions) {
?>
<option value="<?php echo $regions['scat_id'];?>"><?php echo $regions['scat_name'];?></option>
<?php
}
?>
</select>