Question

我在“广告资源”表格中创建了一个包含所有产品的下拉列表。选择产品后，应显示一个表格，显示产品的销售价格和数量。但是，当我选择产品时，没有任何反应，我找不到代码的问题。

数据库名称：nht

表名：库存

这是我的HTML代码：

<html>
<head>
<script>
function showProduct(str) {
    if (str == "") {
        document.getElementById("txtid").innerHTML = "";
        return;
    } else {
        if (window.XMLHttpRequest) {

            xmlhttp = new XMLHttpRequest();
        } else {

            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
        xmlhttp.onreadystatechange = function() {
            if (this.readyState == 30 && this.status == 200) {
			alert(this.responseText);
	          document.getElementById("txtid").innerHTML = this.responseText;
            }
        };
        xmlhttp.open("GET","getproduct.php?q="+str,true);
        xmlhttp.send();
    }
}
</script>
<body>

<form>
<select name="id" onchange="showProduct(this.value)">
  <option value="">Select a product:</option>
		<option value="1">Alternator Assembly Fuso 4D30</option>
		<option value="2">Alternator Assembly Isuzu V-10</option>
		<option value="3">Alternator Assembly Hino JO8C</option>
		<option value="4">Alternator Assembly Isuzu 4BC2</option>
		<option value="5">Alternator Assembly Fuso 4HF1</option>
		<option value="6">Alternator Brush Toyota AN-11</option>
		<option value="7">Alternator Brush Isuzu AK-6</option>
		<option value="8">Alternator Brush Hino AD-6</option>
		<option value="9">Alternator Brush Fuso AM-22</option>
		<option value="10">Alternator Brush Fuso AH-18</option>
		<option value="11">Armature Assembly Fuso 4D50</option>
		<option value="12">Armature Assembly Isuzu V-10</option>
		<option value="13">Armature Assembly Fuso SDC9</option>
		<option value="14">Armature Assembly Fuso 6D22</option>
		<option value="15">Armature Assembly Hino JOSC	</option>
		<option value="16">Solomoid Switch Isuzu S5-146</option>
		<option value="17">Solomoid Switch Fuso SS-1569</option>
		<option value="18">Solomoid Switch Hino SS-2715</option>
		<option value="19">Solomoid Switch Toyota SS-1200</option>
		<option value="20">Solomoid Switch Fuso SS-1504</option>
		<option value="21">Starter Assembly Fuso 4D30</option>
		<option value="22">Starter Assembly Isuzu V-10</option>
		<option value="23">Starter Assembly Hino JO8C</option>
		<option value="24">Starter Assembly Toyota 2C</option>
		<option value="25">Starter Assembly Isuzu 4BC2</option>
		<option value="26">Starter Carbon Brush Fuso 4D30 SM-56	</option>
		<option value="27">Starter Carbon Brush Isuzu X-10 SK-29</option>
		<option value="28">Starter Carbon Brush Fuso 8DC9 SM-J7</option>
		<option value="29">Starter Carbon Brush Isuzu 6BBI SK-14</option>
		<option value="30">Starter Carbon Brush Hino JO8 SD-81</option>
  </select>
</form>
<br>
<div id="txtid"><b>Details</b></div>

</body>
</html>

和php的代码：

<!DOCTYPE html>
<html>
<head>
<style>
table {
    width: 100%;
    border-collapse: collapse;
}

table, td, th {
    border: 1px solid black;
    padding: 5px;
}

th {text-align: left;}
</style>
</head>
<body>

<?php
$q = intval($_GET['q']);

$con = mysqli_connect('localhost','root','','nht');
if (!$con) {
    die('Could not connect: ' . mysqli_error($con));
}

mysqli_select_db($con,"ajax");
$sql="SELECT * FROM inventory WHERE id = '".$q."'";
$result = mysqli_query($con,$sql);

echo "<table>
<tr>
<th>Cost</th>
<th>Quantity</th>
</tr>";
while($row = mysqli_fetch_array($result)) {
    echo "<tr>";
    echo "<td>" . $row['Selling_Price'] . "</td>";
    echo "<td>" . $row['Quantity'] . "</td>";
    echo "</tr>";
}
echo "</table>";
mysqli_close($con);
?>

</body>
</html>

请帮助，因为我真的觉得我错过了什么。

Answer 1

尝试改变这一点：

    if (this.readyState == 30 && this.status == 200) {
      alert(this.responseText);
      document.getElementById("txtid").innerHTML = this.responseText;
    }

到此：

if (this.readyState == 4) {
    if (this.status == 200 || this.status == 304) {
        alert(this.responseText);
        document.getElementById("txtid").innerHTML = this.responseText;
    }
}

下拉列表不显示来自已连接数据库的数据

1 个答案: