search form action url not display php variable - php

Question

hi can anyone tell me whats problem in this form . its not show varible in url
<form class="navbar-form navbar-left" method="post" action="test.php?q=<?php echo $searchb;?>" role="search" style="padding: 3.5px 90px;">
<div class="form-group">
<input type="text" name="searchb" class="form-control" autocomplete="off" placeholder="Search" />
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
php code here
if (isset($_POST['searchb'])) {
$searchb = $_POST['searchb'];
}
when something input in form and action url not show any value
test.php?q=
but we echo variable its show value .

Answer 1

First time that form loaded $_POST['searchb'] is empty so action is equal test.php?q= after load form when you submit form then $_POST['searchb'] to be filled

Answer 2

The Part: action="test.php?q=<?php echo $searchb;?>" is first illogical and most importantly unnecessary since you are POSTing your form. It would have been valid if $searchb was pre-defined. However, since it is a part of the Form; it will always be NULL since it was never declared but expected to be dynamically added on Form-Submit, which wouldn't happen. You do it in one of the 2 ways:
OPTION #1 - PASSING q VIA HIDDEN INPUT:
<!-- YOU DON'T NEED THE echo $searchb PART IN YOUR FORM'S ACTION BECAUSE -->
<!-- THAT VALUE IS NOT PART OF THE ACTION AS IT IS NOT EVEN SET AT ALL -->
<form class="navbar-form navbar-left" method="post" action="test.php" role="search" style="padding: 3.5px 90px;">
<div class="form-group">
<input type="text" name="searchb" class="form-control" autocomplete="off" placeholder="Search" />
<!-- ADD THE q AS HIDDEN INPUT ELEMENT WITH A VALUE -->
<input type="HIDDEN" name="q" value="Some value" />
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
<?php
// INSIDE OF test.php SCRIPT; DO;
if (isset($_POST['searchb'])) {
$searchb = $_POST['searchb'];
}
OPTION #2: USING GET & SETTING Q TO A PRE-DEFINED VALUE
<?php $param = "some-predefined-value"; ?>
<form class="navbar-form navbar-left" method="GET" action="test.php?<?php echo $param;?>" role="search" style="padding: 3.5px 90px;">
<div class="form-group">
<input type="text" name="searchb" class="form-control" autocomplete="off" placeholder="Search" />
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
<?php
// INSIDE OF test.php SCRIPT; DO;
// BUT REMEMBER TO CHECK INSIDE THE `GET` GLOBAL
if (isset($_GET['searchb'])) {
$searchb = $_GET['searchb'];
}
BETTER OPTION FOR YOUR USE-CASE: USING GET & SETTING Q FROM THE INPUT
<!-- STILL NO NEED FOR SETTING QUERY PARAMETERS MANUALLY-->
<!-- THE GET METHOD WOULD TAKE CARE OF THAT FOR YOU ONCE THE FORM IS SUBMITTED -->
<form class="navbar-form navbar-left" method="GET" action="test.php" role="search" style="padding: 3.5px 90px;">
<div class="form-group">
<!-- NOTICE THAT THE NAME OF THE INPUT FIELD CHANGED TO; q HERE -->
<input type="text" name="q" class="form-control" autocomplete="off" placeholder="Search" />
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
<?php
// INSIDE OF test.php SCRIPT; DO;
// BUT REMEMBER TO CHECK INSIDE THE `GET` GLOBAL
if (isset($_GET['q'])) {
$searchb = $_GET['q'];
}