选择国家/地区下拉列表会显示包含多个选项的州列表框，而无需刷新页面。但是选择 2 或 3 个州不会在另一个列表框中显示所有城市。仅显示一个州的城市。帮助
loadData.php
<?php
$q = $_GET['q'];
$con = mysqli_connect('localhost','root','','test');
if (!$con) {
die('Could not connect: ' . mysqli_error($con));
}
mysqli_select_db($con,"test");
$sql="SELECT * FROM state WHERE country_id = '".$q."'";
$result = mysqli_query($con,$sql);
echo "<select name='try[]' onchange='showSecondUser(this.value)' multiple>";
while($row = mysqli_fetch_array($result)){
echo "<option value='".$row['id']."'>".$row['state_name']."</option>";
}
echo" </select>";
$g = $_GET['g'];
$sql="SELECT * FROM city WHERE state_id = '".$g."'";
$result = mysqli_query($con,$sql);
echo "<select name='try' multiple>";
while($row = mysqli_fetch_array($result)){
echo "<option value=''>".$row['city_name']."</option>";
}
echo" </select>";
mysqli_close($con);
?>
index.php
<html>
<head>
<script>
function showUser(str) {
if (str=="") {
document.getElementById("txtHint").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("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","loadData.php?q="+str,true);
xmlhttp.send();
}
function showSecondUser(str) {
if (str=="") {
document.getElementById("txtHint2").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("txtHint2").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","loadData.php?g="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>
<form>
<select name="users" onchange="showUser(this.value)">
<option value="">Select Country</option>
<option value="1">Australia</option>
<option value="2">Japan</option>
<option value="3">Russia</option>
<option value="4">Germany</option>
</select>
</form>
<br>
<div id="txtHint"></div>
<div id="txtHint2"></div>
</body>
</html>
最佳答案
这是因为mysql查询错误。您在简单的等号中提供了多个数字。
应该是:
$g = $_GET['g'];
$sql="SELECT * FROM city WHERE state_id IN (".$g.")";
$result = mysqli_query($con,$sql);
如果 $g 是逗号分隔的数字列表。 如果不是，你必须这样做。
因此，如果 $g 是一个数组，您必须对其执行 implode()，然后才能在查询中使用它
$g = $_GET['g'];
$g = implode(',', $g);
$sql="SELECT * FROM city WHERE state_id IN (".$g.")";
$result = mysqli_query($con,$sql);
如果它是一个字符串，并且可以说数字是用空格分隔的，而不是用逗号替换空格:
$g = $_GET['g'];
$g = str_replace(' ', ',', $g);
$sql="SELECT * FROM city WHERE state_id IN (".$g.")";
$result = mysqli_query($con,$sql);
所以在你的情况下，MySQL 查询应该是这样的:
$sql="SELECT * FROM state WHERE country_id = '".$q."'";
$result = mysqli_query($con,$sql);
echo "<select name='try[]' onchange='showSecondUser(this)' multiple>";
// there is a change here ^
while($row = mysqli_fetch_array($result)){
echo "<option value='".$row['id']."'>".$row['state_name']."</option>";
}
echo" </select>";
/*######################################################*/
$g = $_GET['g'];
$sql="SELECT * FROM city WHERE state_id IN (".$g.")";
$result = mysqli_query($con,$sql);
JavaScript 应该是这样的:
function showSecondUser(str){
var xmlhttp;
if (window.XMLHttpRequest) {
xmlhttp = new XMLHttpRequest();
} else {
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange = function () {
if (xmlhttp.readyState === 4 && xmlhttp.status === 200) {
document.getElementById("txtHint2").innerHTML = xmlhttp.responseText;
}
}
var values = new Array();
for (var i=0; i < str.options.length; i++) {
cur = sel.options[i];
if (cur.selected) {
values.push(cur.value);
}
}
if (values.length) {
values = values.join(",");
} else {
values = null;
}
xmlhttp.open("GET","loadData.php?g="+values,true);
xmlhttp.send();
}
关于javascript - 状态的多选列表框不显示另一个列表框中的所有城市(Php，mysql，ajax)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26305937/