php - 我如何使用ajax和php从选择选项中获取值(value)

Question

我有 2 个选择框选项，城市和地区。当我选择城市时，我使用ajax go get 地区名称。对于这个过程，我已经成功，但是当我单击“提交”时，我收到错误消息“未定义索引:区”，如这张图片所示 result image .

这是我的ajax代码:

 $(document).ready(function($) {
    $("#city").change(function() {
        var search_id = $(this).val();
        $.ajax({
            url: "search.php",
            method: "post",
            data: {search_id:search_id},
            success: function(data){
                $("#district").html(data);
            }
        })
    });
});

这是 HTML 代码:

   

 <form action="" method="post">
    select city:
    <select name="city" id="city">
    	<option value="1">Phnom Penh</option>
    	<option value="2">Kampong Soam</option>
      <option value="3">Siem Reap</option>
    </select>

    select district:
    <select name="distrcit" name="district" id="district">
    	<option>Select District</option>
    </select>

    <input type="submit" name="submit">
    </form>

这是 PHP 代码:

<?php 
if(isset($_POST['submit'])){
	echo $_POST['city'];
	echo $_POST['district'];
}

 ?>

//ajax request
<?php 
if(isset($_POST['search_id'])){
	$search_id = $database->escape_string($_POST['search_id']);

	if(!empty($search_id)){
		// $output = array();
		$sql = "SELECT * FROM district WHERE ref_id = '$search_id'";
		$districts = District::find_this_query($sql);
		foreach($districts as $district){
			// echo $district->id;
			// echo $district->district_name;
			$output .= "<option value='{$district->id}'>{$district->district_name}</option>";
		}

		echo $output;
	}
	
 }
?>

Answer 1

您已在选择框中设置名称两次。仅分配名称一次:

所以做到:

<select name="district" id="district">
    <option>Select District</option>
</select>