AJAX使用从PHP生成的HTML调用的函数来更新MYSQL数据库

问题描述：

我有一个php页面，用于生成和显示表格.对于表格的最后一行，我想显示带有"onclick"功能的图像.这会将所选行的用户名发送到脚本，该脚本将使用AJAX更新数据库.该表显示正常，但AJAX无法正常工作.我的显示图片的php是:

I have a php page generating and displaying a table. for the last row in the table i want to display an image with an 'onclick' function attached. this will send the username for the selected row to a script that will use AJAX to update a database. The table displays fine but the AJAX is not working. my php to display the image is:

echo "<td> <img id='tblimg' 
    onclick='like('" . $row['Username'] . "')' 
    src='like.jpg' alt='like/dislike image' 
    width='80px' height='30px'></td>";

javascript函数是:

The javascript function is:

<script type="text/javascript" >

        function like(user) 
        {

            $.ajax(
                url: "update.php",
                type: "POST",
                data: { 'username': user, 'liked': '1' },                   
                success: function()
                            {
                                alert("ok");                                    
                            }
            );
        }

</script>

这是update.php:

And here is update.php:

<?php

$con=mysqli_connect("","sam74","********","sam74");

// Check connection
if (mysqli_connect_errno())
{
    echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

$Username = $_POST['username'];
$Liked = $_POST['liked'];   

$sql = "UPDATE 'followers' SET 'Liked' = '$Liked' WHERE 'Username' = '$Username'";

if (!mysqli_query($con,$sql))
{
    die('Error: ' . mysqli_error($con));
}

mysqli_close($con);

答

此代码中有一些错误，请允许我逐行帮助您.

There are some mistakes in this code, let me help you line by line.

echo "<td> <img id='tblimg' 
onclick=\'like('" . $row['Username'] . "');\' 
src='like.jpg' alt='like/dislike image' 
width='80px' height='30px'></td>";

javascript函数是:

The javascript function is:

先转义onclick事件的报价

Escape your quotes for the onclick event first

    function like(user) 
    {

        $.ajax({
            url: "update.php",
            type: "POST",
            data: { 'username': user, 'liked': '1' },                   
            success: function()
                        {
                            alert("ok");                                    
                        }
        });
    }

将{和}添加到ajax调用

add { and } to the ajax call

从表名和字段中删除引号

Remove the quotes from table name and fields

$sql = "UPDATE followers SET Liked = '$Liked' WHERE Username = '$Username'";

在ajax成功执行以及函数启动之后，您始终可以打印一条消息，以查看函数是否正在被调用，并且如果php脚本返回了一些错误，请为此使用警报

in ajax success and after the function begins, you can always print a message to see if your function is being called, and if php script is returning some error, use an alert for that

更新

success: function(data){
   alert(data); // this will print you any php / mysql error as an alert                                    
}

更新2

像这样编写onclick选项.

Write your onclick option like this.

echo "<img onclick=\"like('" . $row['Username']. "');\" 
src='like.jpg' alt='like/dislike image' 
width='80px' height='30px' />";

AJAX使用从PHP生成的HTML调用的函数来更新MYSQL数据库

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