当表单提交时，您需要从 $ _ POST array

您可以执行 print_r（$ _ POST）来查看它包含的所有内容（所有表单域）和

用户名将会是 $ _ POST ['username']

我推荐阅读使用表单和PHP的教程... 这是一个很好的选择

既然你明显是初学者，我会帮你多一点：

为您的提交按钮命名：

 < form enctype =multipart / form-data动作=method =post> 
< input name =usernametype =text/> 
< input type =submitname =submitvalue =Uploadclass =btn btn-primary/>< br /> 
< / form> 
 

因为 action 为空，所以POST到当前页面。在你的文件的顶部，你可以通过检查是否设置了 $ _ POST ['submit'] '来检查表单是否被提交。 ）。
$ b $ pre $ if（isset（$ _ POST ['submit']））{
// form submitted，now我们可以查看通过
得到的数据//括号内的值来自输入字段的name属性。 （就像上面提交）
$ username = $ _POST ['username'];

//现在你可以对这个变量做任何事情。
}
//关闭PHP标记，您的HTML将低于


I have an HTML form as follows:

<form enctype="multipart/form-data" action=" " method="post">
<input name="username" type="text"/>
<input type="submit" value="Upload" class="btn btn-primary"/><br/>
</form>

and I want that the user of this form enters data in the input box. Then I would like this data to be the value of a PHP string - e.g. $username = "MY_NAME"; where MY_NAME is the value of the HTML form entered by the user.

If the input by the user in the input box is e.g. "***" I want the PHP string to be $username = "***";

Thanks in advance.

When the form submits, you need to get the values from the $_POST array

You can do print_r($_POST) to see everything it contains (all of the form fields) and reference them individually as well.

Username will be $_POST['username']

I recommend reading a tutorial on working with forms and PHP... here's a good one

Since you're obviously a beginner I'll help you out a bit more:

Give your submit button a name:

<form enctype="multipart/form-data" action="" method="post">
    <input name="username" type="text"/>
    <input type="submit" name="submit" value="Upload" class="btn btn-primary"/><br/>
</form>

Because action is blank, it will POST to the current page. At the top of your file, you can check to see if the form was submitted by checking if $_POST['submit'] is set (I gave your submit button that name).

if(isset($_POST['submit'])) {
    // form submitted, now we can look at the data that came through
    // the value inside the brackets comes from the name attribute of the input field. (just like submit above)
    $username = $_POST['username'];

    // Now you can do whatever with this variable.
}
// close the PHP tag and your HTML will be below