PHP $_POST function not recognizing HTML form input value

I can't seem to apply the $_POST function properly to retrieve the data from a simple HTML form. I'm new to PHP, so I may be overlooking something simple.

我似乎无法正确应用$ _POST函数从简单的HTML表单中检索数据。我是PHP的新手,所以我可能会忽略一些简单的东西。

I have a form with action directing to the same page, but if the form is filled out, the value of $_POST['input_name'] will have changed, so I can trigger the php function using that condition. Is this the best way to structure this kind of action?

我有一个带有动作的表单指向同一页面,但是如果填写了表单,$ _POST ['input_name']的值将会改变,所以我可以使用该条件触发php函数。这是构建这种行为的最佳方式吗?

Here's my HTML code (thispage.php is the current/same page):

这是我的HTML代码(thispage.php是当前/同一页面):

<form action="thispage.php" method="post">
  Name: <input type="text" name="userName" id="userName" />
  <input type="submit" />
</form>

Here's my PHP code from the same page:

这是我在同一页面上的PHP代码:

if("" == trim($_POST['userName'])){
  echo $_POST['userName'];
}

Thanks a lot in advance!!

非常感谢提前!!

4 个解决方案

#1

First remove the action from form if your server side code is in the same page. And Use the empty() or isset() functions for checking the value.

如果服务器端代码在同一页面中,请首先从表单中删除操作。并使用empty()或isset()函数来检查值。

For Example:

if(!empty(trim($_POST['userName']))){
  echo $_POST['userName'];
}

if(isset(trim($_POST['userName']))){
  echo $_POST['userName'];
}

#2

if("" == trim($_POST['userName'])){
  echo $_POST['userName'];
}

This is actually checking if the value is empty and echoes it if it is.

这实际上是检查值是否为空并且如果是,则回显它。

You probably want to use !empty($_POST['userName']) to check if it's not empty and then echo it if it is not.

您可能想要使用!empty($ _ POST ['userName'])来检查它是否为空,然后如果不是则回显它。

#3

try this:

HTML code

<form action="thispage.php" method="post">
  Name: <input type="text" name="userName" id="userName" />
  <input type="submit" name="submit" />
</form>

PHP code on the same page:

同一页面上的PHP代码:

if(isset($_POST['submit']))
{
    if(isset(trim($_POST['userName']))){
        echo $_POST['userName'];
    }
}

#4

Try this...

if(trim($_POST['userName']) != ' '){
    echo $_POST['userName'];
}

#1