Question

   <form action="" method="post">
            <div class="form-group">
                <div class="input-group">
                <span class="input-group-addon"><i class="fa fa-user fa-fw"></i></span>
                <input class="form-control" type="text" placeholder="Enter your username here..." name="username">
                </div>
            </div>
            <div class="form-group <?php //apply php code later ?>"> 
                <div class="input-group">
                <span class="input-group-addon"><i class="fa fa-envelope fa-fw"></i></span>
                <input class="form-control" type="text" placeholder="Enter your email here..." name="email">
                </div>
            </div>
            <div class="form-group <?php //apply php code later ?>">
                <div class="input-group">
                <span class="input-group-addon"><i class="fa fa-key fa-fw"></i></span>
                <input class="form-control" type="text" placeholder="Enter your password here..." name="password">
                </div>
            </div>
            <div class="form-group <?php //apply php code later ?>"> 
                <div class="input-group">
                <span class="input-group-addon"><i class="fa fa-key fa-fw"></i></span>
                <input class="form-control" type="text" placeholder="Retype your password here..." name="password_retype">
                </div>
            </div>
            <hr class="linestyle">
            <p>Which comparison operator is used to compare variables/values in PHP?</p>
            <div class="form-group">
                <input class="form-control" type="text" placeholder="Answer the question here..." name="question">
            </div>
            <div class="checkbox">
                <label>
                    <input type="checkbox" name="checkbox">I agree to the <a href="#">rules</a> of this forum.
                </label>
            </div>
            <p class="rules" style="font-size:10px;">Breaking the rules by any means will result in a permanent ban.</p>
            <input class="btn btn-success fullwidth" type="submit" value="Register">
        </form>

我想在提交此表单后应用其中提到的一些代码。因此，例如，如果我的查询说具有该用户名的用户已经存在，我想在这些类中应用一些引导程序。我怎么能用PHP做到这一点？

Answer 1

这假设您回发到action=''暗示的同一页面。

您可以执行以下操作：

<div class="form-group <?php if(isset($_POST)) { echo 'posted-class'; } ?>">

但是，既然你要多次使用它，你可能想在顶部定义一个变量：

<?php
$classAfterPosted = ''; //default blank
if(isset($_POST))
{
  $classAfterPosted = 'posted-class'; 
} 
?>
...
 <div class="form-group <?php echo $classAfterPosted; ?>">

如何在用PHP提交表单后更改css类？

1 个答案: