如何根据php条件显示和隐藏div

Question

我的 php 代码

<?php

session_start();

if(isset($_SESSION["loggedin"]) && $_SESSION["loggedin"] === true){

    echo "logged in";

?>

    <script>

        document.getElementById("loggedin").style.display = 'none';

    </script>

<?php

}

else {

    echo "not logged in";

?>

    <script language="javascript">

        document.getElementById("public").style.display = 'none';

    </script>

<?php

}    

?>

和 html 是

<li>

        <div style="float:right;display:block;" id="public">

             <a href="login_signup/login.php" class="myButton">   Login   </a>

                     </div>

                     <div style="float:right;display:block;" id="loggedin">

                  <a href="login_signup/login.php" class="myButton">   Loggedin   </a>

                         </div>

                </li>

我只想一次显示一个 div。如何解决这个问题？？但是 php echo 功能是根据条件工作的。

Answer 1

不要将 JavaScript 代码放入 PHP 中，只需将 div 放入其中即可。<?phpsession_start();?><li><?phpif(isset($_SESSION["loggedin"]) && $_SESSION["loggedin"] === true) {?>&nbsp; &nbsp; <div style="float:right;display:block;" id="loggedin">&nbsp; &nbsp; &nbsp; &nbsp; <a href="login_signup/login.php" class="myButton">&nbsp; &nbsp;Loggedin&nbsp; &nbsp;</a>&nbsp; &nbsp; </div><?php} else {?>&nbsp; &nbsp; <div style="float:right;display:block;" id="public">&nbsp; &nbsp; &nbsp; &nbsp; <a href="login_signup/login.php" class="myButton">&nbsp; &nbsp;Login&nbsp; &nbsp;</a>&nbsp; &nbsp; </div><?php}&nbsp; &nbsp;&nbsp;?></li>

Answer 2

让 PHP 来处理工作，完全不涉及 JavaScript。session_start();if(isset($_SESSION["loggedin"]) && $_SESSION["loggedin"] == true){&nbsp; &nbsp; echo '<div style="float:right; display:block;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<a href="login_signup/login.php" class="myButton">Login</a>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </div>';&nbsp; &nbsp; } else {&nbsp; &nbsp; echo '<div style="float:right; display:block;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<a href="login_signup/login.php" class="myButton">Loggedin</a>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </div>';}

Answer 3

你可以用 php 包裹你的 div<li>&nbsp; &nbsp; <?if(($_SESSION["loggedin"]??false) === true):?>&nbsp; &nbsp; &nbsp; &nbsp; <div style="float:right;display:block;" id="loggedin">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <a href="login_signup/login.php" class="myButton"> Loggedin </a>&nbsp; &nbsp; &nbsp; &nbsp; </div>&nbsp; &nbsp; <?else:?>&nbsp; &nbsp; &nbsp; &nbsp; <div style="float:right;display:block;" id="public">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <a href="login_signup/login.php" class="myButton"> Login </a>&nbsp; &nbsp; &nbsp; &nbsp; </div>&nbsp; &nbsp; <?endif;?></li>