<div id="test"></div>
<script>
  $(document).ready(function() {
    alert($('#test').id);
  });  
</script>

为什么上面的方法不起作用,我应该怎么做?


当前回答

<html>
<head>
  <link rel="stylesheet"href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
    </head>
<?php
    // include Database connection file 
    include("db_connection.php");

    // Design initial table header 
    $data = '<table class="table table-bordered table-striped">
                        <tr>
                            <th>No.</th>
                            <th>First Name</th>
                            <th>Last Name</th>
                            <th>Email Address</th>
                            <th>Update</th>
                            <th>Delete</th>
                        </tr>';
    $query = "SELECT * FROM users";
    if (!$result = mysqli_query($con, $query)) {
        exit(mysqli_error($con));
    }
    // if query results contains rows then featch those rows 
    if(mysqli_num_rows($result) > 0)
    {
        $number = 1;
        while($row = mysqli_fetch_assoc($result))
        {
            $data .= '<tr>
                <td>'.$number.'</td>
                <td>'.$row['first_name'].'</td>
                <td>'.$row['last_name'].'</td>
                <td>'.$row['email'].'</td>
                    <td><button onclick="DeleteUser('.$row['id'].')" class="btn btn-danger">Delete</button>
                </td>
            </tr>';
            $number++;
        }
    }

    else
    {
        // records now found 
        $data .= '<tr><td colspan="6">Records not found!</td></tr>';
    }

    $data .= '</table>';
    echo $data;
?>

<script type="text/javascript">

    function DeleteUser(id) {
    var conf = confirm("Are you sure, do you really want to delete User?");
    if (conf == true) {
        $.ajax({
                    url:'deleteUser.php',
                    method:'POST',
                    data:{
                        id:id
                    },
            success:function(data){
                      alert('delete successfully');
                   }




}
});

deleteUser.php

<?php
// check request
if(isset($_POST['id']) && isset($_POST['id']) != "")
{
    // include Database connection file
    include("db_connection.php");

    // get user id
    $user_id = $_POST['id'];

    // delete User
    $query = "DELETE FROM users WHERE id = '$user_id'";
    if (!$result = mysqli_query($con, $query)) {
        exit(mysqli_error($con));
    }
}
?>

其他回答

这是一个老问题,但截至2015年,这可能会奏效:

$('#test').id;

您还可以分配任务:

$('#test').id = "abc";

只要定义以下JQuery插件:

Object.defineProperty($.fn, 'id', {
    get: function () { return this.attr("id"); },
    set: function (newValue) { this.attr("id", newValue); }
});

有趣的是,如果元素是DOM元素,那么:

element.id === $(element).id; // Is true!

它不会回答OP,但对其他人来说可能很有趣:在这种情况下,您可以访问.id字段:

$('#drop-insert').map((i, o) => o.id)

$('selector').attr('id')将返回第一个匹配元素的id。参考

如果匹配的集合包含多个元素,则可以使用常规的.each迭代器返回包含每个id的数组:

var retval = []
$('selector').each(function(){
  retval.push($(this).attr('id'))
})
return retval

或者,如果你想变得更强硬一点,你可以避免包装,使用.map快捷方式。

return $('.selector').map(function(index,dom){return dom.id})

.id不是有效的jquery函数。您需要使用.attr()函数来访问元素拥有的属性。您可以使用.attr()通过指定两个参数来更改属性值,或者通过指定一个参数来获取值。

http://api.jquery.com/attr/

$.fn.extend({
    id : function() {
        return this.attr('id');
    }
});

alert( $('#element').id() );

当然需要一些检查代码,但很容易实现!