Dropdown value is not selected on submitting form in php - php

Question

The scenario is - I have a form with multiple input fields and text areas and whenever I post this form all these values will get posted. However, I also have a dropdown that I create from my database. This dropdown value shows up properly when I get the values. I have a second submit button, which should take this selected value and post to other page.
I have tried the $_POST='name of select option' but it did not help.
I have a onlick for directing the form to other page for updating the db.
I'm fairly new to php, so it could be the use of _POST that could be incorrect.
<form name="f1" class="formoid-solid-blue" method="GET">
<div class="title">
<h2></h2>
<h2>Tracking & Receiving</h2>
</div>
<div class="element-input">
<label class="title"></label>
<div class="item-cont">
<input class="small" type="text" name="store" placeholder="Store #"/>
<span class="icon-place"></span>
</div>
</div>
<div class="element-input">
<label class="title"></label>
<div class="item-cont">
<input class="medium" type="text" name="userid" placeholder="UserId"/>
<span class="icon-place"></span>
</div>
</div>
<div class="element-input">
<label class="title"></label>
<div class="item-cont">
<input class="large" type="text" name="order" placeholder="Order Number"/>
<span class="icon-place"></span>
</div>
</div>
<div class="submit">
<input type="submit" name="Send" value="Send"/>
</div>
<div class="element-separator">
<hr>
<h3 class="section-break-title">Tracking Numbers</h3>
</div>
<div class="element-multiple">
<label class="title"></label>
<div class="item-cont">
<div class="large">
<select data-no-selected="Nothing selected" name="updTR" multiple="multiple">
<option name="op" value="<?php require 'connection.php'; ?>"> //getting value form db
<?php
echo $trackID; //DB value
$trackID = $_GET['updTR']; //getting the variable from the form
?></option>
</select>
<span class="icon-place"></span>
</div>
</div>
</div>
<div class="submit">
<input type="submit" onclick="f1.action='UpdateTR.php'; return true;" name="UpdateTR" value`enter code here`="Submit"/>
</div>
</form>

Answer 1

Well, looking at the form, you said you are using POST, and tested with other POST related method, but your form is using GET, as seen on your code above.
Since you are new to PHP, as an example, if you are using post, and a variable is waiting on the other page to collect this information from your form then you do it like this:
This is the form field example:
<input type="text" name="XYZ">
Then on the page that will collect this info, it would be
$someVariable = $_POST[ 'XYZ' ];
now, if you want to use GET, then its the same thing but you use this
$someVariable = $_GET[ 'XYZ' ];
hope this clears the confusion.
-- EDIT 2 --
Ok after reading your comment, and since i haven't seen how you are iterating through your DB for the options that go in that "option" list/menu, I'm going to say you cant put "connection" as the value on this part:
<option name="op" value="<?php require 'connection.php'; ?>">
because assuming that "connection.php" is connecting to the DB, then that wont help you, that goes elsewhere. Instead, once you've made that connection(elsewhere, preferably above it in the header somewhere), you then have to have code that loops through the DB, and "WHILE" its looping, spit out results into that options field. Let me give you an example with PSEUDO code.
If a normal select/option code looks like this
<select>
<option> option 1 </option>
<option> option 2 </option>
</select>
etc, then you need php that loops through your DB results, and puts the results into the "options" in that select,
here is some pseudo code:
<select>
<?php
while($row = your fetch code here){
echo "<option>your line items here</option>";
}
?>
</select>
OR.....
if "$row" has a specific value you want to use from the database that you visually want to add in that list, then you could do similar to above but with something like:
<select>
<?php
while($row = your fetch code here){
echo "<option>your line items here "' . $row['some value from DB here'] . '"</option>";
}
?>
</select>
etc.
Essentially, you want your "while loop" to iterate through your database and WHILE its doing it, to input its data into your options html.
ALSO, if you wanted a particular value from your DB, put into a GET variable, to use for the processing page (as i mentioned all the way above), then again, similarly, you can do something like this:
<?php
while($row = your fetch code here){
echo "<a href='linkHere.php?yourVariableToTrackWithGetHere='".$row['yourDBresutlToTrack']."'> Your text here </a>"; }
?>
This way, when you click the link, the database value gets added to that variable that you can call later in the processing page.
Kinda long winded but, this should set you 100% straight.
Hope this helps.