Question

If I use isset() for a text input then I write it like this:

$newpass = (isset($_POST['newpass'])) ? $_POST['newpass'] : '';

Now if I have a drop down menu like below:

<select name="students">
<option value="">Please Select</option>
<option value="john">John Doe</option>
<option value="Mike">Mike Smith</option>
</select>

Then can I use the same type of isset as I have used for text input:

$studentsdrop = (isset($_POST['students'])) ? $_POST['students'] : '';

or is the isset different fro a drop down menu?

Answer 1

isset() checks to see if a variable exists and that it is not set to NULL. It is not related to HTML at all.

In your case:

$studentsdrop = (isset($_POST['students'])) ? $_POST['students'] : '';

As long as you knew that students was going to be present you wouldn’t need this.
The most common time isset() is used upon form submits, is determining a checkbox. For example if you submit a form that has a checkbox, and that checkbox was not checked, it would not be passed into the $_POST variable. This is crucial to use:

$checkbox_name = isset($_POST['checkbox_name']) ? $_POST['checkbox_name'] : '';

In the case of a select the $_POST variable will always return, even if it is empty.