javascript 如何通过从另一个下拉列表中选择值来填充下拉列表
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How can i populate a dropdown list by selecting the value from another dropdown list
提问by Ashoka
i have two the 1st one say country
我有两个第一个说国家
country_id country _name
1 India
2 Australia
3 Netherlands
the 2nd table is states
state_id country state name
1 2 abc
2 2 xyz
3 3 pqr
4 1 lmn
5 1 rst
where country_idin the first table is the country in the second table
So now i want two drop downs one for country and another for states. The Second drop down values must must change as per the selected item in the first drop down and the second drop down must be disabled as long as the items in the first drop down is not selected
其中，country_id在第一个表是在第二个表中的国家，所以现在我想要两个下拉菜单一个国家与另一个国家的状态。第二个下拉值必须根据第一个下拉列表中的选定项目进行更改，并且只要未选择第一个下拉列表中的项目，就必须禁用第二个下拉列表
回答by Saranya Sadhasivam
Do a html as given below for Make
为 Make 执行如下所示的 html
<?php $sql = "SELECT * FROM country";
$result = mysql_query($sql);
?>
<select id="country" name='country' onchange="get_states();">
<option value=''>Select</option>
<?php while ($row = mysql_fetch_array($result)) {
echo "<option value='" . $row['country_id'] . "'>" . $row['country_name'] . "</option>";}
?>
</select>
<div id="get_state"></div> // Sub will be appended here using ajax
Write a ajax function get_states();
写一个ajax函数get_states();
<script type="text/javascript">
function get_states() { // Call to ajax function
var country = $('#country').val();
var dataString = "country="+country;
$.ajax({
type: "POST",
url: "getstates.php", // Name of the php files
data: dataString,
success: function(html)
{
$("#get_state").html(html);
}
});
}
</script>
File getstates.php - Will get sub from the below file which will be appended to the div
文件 getstates.php - 将从下面的文件中获取子文件，该文件将附加到 div
if ($_POST) {
$country = $_POST['country'];
if ($country != '') {
$sql1 = "SELECT * FROM state WHERE country=" . $country;
$result1 = mysql_query($sql1);
echo "<select name='state'>";
echo "<option value=''>Select</option>";
while ($row = mysql_fetch_array($result1)) {
echo "<option value='" . $row['state_id'] . "'>" . $row['state_name'] . "</option>";}
echo "</select>";
}
else
{
echo '';
}
}
