The value of name in the select drop-down box cannot be obtained in php100_html/css_WEB-ITnose

echo $_POST['f_id'];
?>

Add large category
Add small category

Reply to discussion (solution)

You didn’t write this together, did you? ? This only works if the form is submitted. Your form here has no action address and no submit button. How do you want it to be obtained?

<form action="test.php" method="post"><select name="f_id"><option value="0">添加大类</option><option value="1">添加小类</option></select><input type = "submit" value = "apply" /></form>

Write the php code into a separate php file. I added it to test.php here. Click the apply button and it will be submitted to test.php In the file, the value can be obtained.
Give it a try.

No, you should find a book first and read it carefully~~~