如何使用单个按钮多个发布表单并在新选项卡中全部打开

我有 3 个具有相同功能的后表单，但我做不同的消息，

如何创建一个按钮来执行所有按钮（1,2,3）？ 并且使用单个按钮比打开每个按钮的新选项卡（1,2,3）。

<?php $url = "http://example.com"; ?>
<form id="postform" action="<?php echo "$url" ?>/action.php" method="post" name="postform" target="_blank" enctype="multipart/form-data">
    <table id="message">
        <tbody id="post-message">
            <div id="post-subject">
                <input type="text" name="subject" id="subject" value="subject 1"></input>
            </div>
            <div id="post-message">
                <textarea name="message" id="code-message">message 1 here</textarea>
            </div>
            <div id="post-buttons">
                <td id="post-buttons"><input type="submit" name="submit" value="button 1"></td>
            </div>
        </tbody>
    </table>
</form>
<form id="postform" action="<?php echo "$url" ?>/action.php" method="post" name="postform" target="_blank" enctype="multipart/form-data">
    <table id="message">
        <tbody id="post-message">
            <div id="post-subject">
                <input type="text" name="subject" id="subject" value="subject 2"></input>
            </div>
            <div id="post-message">
                <textarea name="message" id="code-message">message 2 here</textarea>
            </div>
            <div id="post-buttons">
                <td id="post-buttons"><input type="submit" name="submit" value="button 2"></td>
            </div>
        </tbody>
    </table>
</form>
<form id="postform" action="<?php echo "$url" ?>/action.php" method="post" name="postform" target="_blank" enctype="multipart/form-data">
    <table id="message">
        <tbody id="post-message">
            <div id="post-subject">
                <input type="text" name="subject" id="subject" value="subject 3"></input>
            </div>
            <div id="post-message">
                <textarea name="message" id="code-message">message 3 here</textarea>
            </div>
            <div id="post-buttons">
                <td id="post-buttons"><input type="submit" name="submit" value="button 3"></td>
            </div>
        </tbody>
    </table>
</form>

感谢您的帮助。