传递在一个PHP文件中收集的参数将作为电子邮件发送到另一个PHP中

I'm collecting an argument from a signup URL using '?' like this,

.../signup.php?id=6489

now i'm collecting this 'id' in my php in this way,

<?php
    $id = $_GET['id'];
    // echo $id;
?>

Now i want to use this $id in another PHP file - code_exec.php where there is a mail() function which emails this and other parameters collected from a form. Now the parameters collected from the Form work great and they all show properly in the email. However this ID variable does not. I have included the signup.php in code_exec.php using this,

include 'signup.php';

and yet it doesn't seem to work. What am I doing wrong here?

Without showing what's in signup.php and how you're using that $id value, we can't help. But the obvious one: If the signup.php stuff is working inside a function, then you're subject to PHP's scoping rules and will have to make $id a global, eg.

$id = $_GET['id'];

function email() {
   global $id;
   blah blah blah
}

// foo.php
$id = '12345';
include 'bar.php';

// bar.php
echo $id;

Will output 12345. Any variables that exist in scope of the include/require call will be available in the included file.

Add a hidden input value to your form and assign it the passed id value, something like this:

<input type="hidden" id="id" name="id" value="<?php echo $id ?>" />

From what it sounds like, you go to signup.php?id=6489, fill out a form which submits to code_exec.php and you want to get the ID in code_exec.php.

If that is the case, you can include a hidden form field in the signup page with that ID.

<input type="hidden" name="id" value="<?php echo $_GET['id']; ?>" />

and that will get submitted with the form just like all of the other fields. Make sure to sanitize your inputs!