如何从依赖下拉列表获取值到JavaScript并将其解析到另一个PHP页面 - how to get value from dependant drop down list to javascript and parsing it to another php page?

how to get value from dependant drop down list to javascript and parsing it to another php page?

我做了一个 2 级依赖的下拉列表，工作正常，但我不知道如何使用 javascript 获取 2 级值。这是我正在使用的代码。

下拉列表.html：

<script type="text/javascript" src="../js/dropdown_list.js"></script>
<select class="level" id="level1" onChange="get_level2(this.value)">
    <option selected="selected" value="0">--Choose One--</option>
<?php
$sql_get = mysql_query ("SELECT * FROM ajax_table WHERE pid=0");
    while($row_get = mysql_fetch_array($sql_get))
    {
        echo "<option value='".$row_get['id']."'>".$row_get['category']."</option>";
    }
    ?>
    </select>
    <span id="level2"></span>

因为家属工作得很好..所以我想我可以跳过get_level2 ()函数和另一个 php 文件来处理第二级下拉菜单。.

这是我尝试在单击按钮时从下拉列表中获取值的代码。

dropdown_list.js ：

function cekForm() {
//the getValue1 work fine but I can't make getValue2 work..
//how to get value from 2nd level drop down list with getValue2??
var value1 = document.getElementById("level1");
var getValue1 = value1.options[value1.selectedIndex].value;
var value2 = document.getElementById("level2");
var getValue2 = value2.options[value2.selectedIndex].value;
if (getValue1 == 0){
alert("Please Choose One");
}
if (getValue1 != 0){
//where I want to pass the dropdown value to post_value.php
window.location= "post_value.php";
}
}

如何获取第二级下拉列表的值？以及如何将值传递给post_value.php？？

请帮帮我...

更新：

以下是来自火狐视图页面源代码的代码：

//this is <head> part
  <link href="../css/val.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="../js/jquery-2.0.3.min.js"></script>
<script type="text/javascript" src="../js/dropdown_list.js"></script>
//end of </head>
//<body> part
<div class="form-div">
    <form id="form_level" name="form_level" style="padding-top:0px;">
    <div class="form-row" style="padding-top:0px;">
    <h3>Choose Drop Down :</h3>
    <select class="level" id="level1" onChange="get_level2(this.value)" style="position:relative; top:-40px; left:150px;">
    <option selected="selected" value="0">--Choose One--</option>
    <option value='1'>BAA</option><option value='2'>BAK</option><option value='3'>BAUK</option></select>
    <span id="level2"></span>
    </div>

      <div class="form-row" style="position:relative; top:100px; left:305px;">
      <input class="submit" value="Send" type="button" onClick="cekForm()">
      </div>
      <br /><br />
    </form>
</div>

通过 url 使用 get 方法传递值

<script>
function cekForm() {
    var getValue1 = document.getElementById("level1").value;
    var getValue2 = document.getElementById("level2").getElementsByTagName("select")[0].value;
    if (getValue1.length==0){
        alert("Please Choose One");
        return;
    }
    if (getValue1.length>0){
        window.location= "post_value.php?level1="+getValue1+"&level2="+getValue2;
    }
}
</script>

并在PHP文件中接收它

post_value.php

<?php
$level1 = $_GET["level1"];
$level2 = $_GET["level2"];
?>