使用jQuery单击表单提交后显示加载gif

Question

表单提交后,我只是想显示一个加载gif.我的代码无法正常显示加载gif.你会看到我的gif图像被设置为visibility: hidden.

<script src="js/jquery-1.11.1.min.js"></script>

<div class="" style="width: 480px; margin: 0 auto; margin-top: 20px;" id="form_wrapper">
    <img src="img/loader.gif" id="gif" style="display: block; margin: 0 auto; width: 100px; visibility: hidden;">
    <div class="fade" id="form">
        <form action="process_login.php" method="POST" name="simplelogin" id="login_form"><br />
            <label for="username">&nbsp; Username:</label>
            <input type="username" name="username" id="username" size="30" required><br><br>
            <label for="password">&nbsp; Password:</label>
            <input type="password" name="password" id="password" size="30" required><br><br>
            <input class="load_button" type="submit" name="submit" id="submit" value="Submit" placeholder="Submit">
        </form>
    </div>
</div>
<div class="fifty"></div>

<script type="text/javascript">
    $('.load_button').submit(function() {
        $('#gif').show(); 
        return true;
    });
</script>

Answer 1

该show()方法仅影响displayCSS设置.如果要设置可见性,则需要直接执行此操作.此外,.load_button元素是一个按钮,不会引发submit事件.您需要将选择器更改form为for for work:

$('#login_form').submit(function() {
    $('#gif').css('visibility', 'visible');
});

Answer 2

按钮输入没有提交事件.尝试将事件处理程序附加到表单:

<script type="text/javascript">
     $('#login_form').submit(function() {
       $('#gif').show(); 
       return true;
     });
 </script>