Isset()函数的问题 [英] Issue With Isset() Function

问题描述

试图通过测试和尝试方法来学习PHP我正在努力解决isset()问题. 这是我的代码:

Trying to learn PHP with test and try method I am struggling with isset(). Here is the code I have:

<form action="validate.php" method="POST">
  <label title="User Input"> Custom Header Name</label>
  <input type="text" name="user_input">
  <button  type="submit" id="pageName">Submit</button>
</form>

PHP文件为

<?php
  if(isset($_POST['user_input']))
    {
     echo "Input Is Set";
    } else{
           echo "Not Yet Set";
          }
?>

我都遇到两种情况(输入为空或填充)，结果是我收到第一条消息输入已设置"！ 您能告诉我为什么会这样吗?

I both cases(empty or filled input) I am getting the first message "Input Is Set" as result! Can you please let me know why this is happening?

推荐答案

这是因为user_input具有isset一旦表单也被提交(如果未填写)，为避免错误，只需添加!empty check

This is because user_input have isset once form is submitted also if it is not filled, to avoid the error simply add an !empty check

if(isset(($_POST['user_input'])) && (!empty($_POST['user_input'])))

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