Default dropdown option and displaying its default values - php

Question

I have a dropdown select box whose values are populated from a field priority from database. Then, there are three div tags in which, display_duration and arrival and dispatch date are calculated according to the option selected shown.
I am able to perform the required functionality, the code is running smoothly but there is one more condition which is Normal should be selected as default option value and its values should be displayed in the div tags by default.
For now, I am not able to set normal as default value and thus, I am not getting its related values in div tag.
Here's my code:
Database:
CREATE TABLE `tblpriority` (
`priority_id` INT(11) NOT NULL AUTO_INCREMENT,
`priority` VARCHAR(15),
`dispatch_interval_days` INT,
`arrival_interval_days` INT,
`display_duration` VARCHAR(50),
`created_at` DATETIME DEFAULT CURRENT_TIMESTAMP,
`updated_at` DATETIME,
PRIMARY KEY (`priority_id`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB
;
Query for inserting values:
INSERT INTO `tblpriority` (`priority`,`dispatch_interval_days`,`arrival_interval_days`,`display_duration`) VALUES ('Normal',40,55,'4-6 Weeks');
INSERT INTO `tblpriority` (`priority`,`dispatch_interval_days`,`arrival_interval_days`,`display_duration`) VALUES ('High',30,45,'3-4 Weeks');
INSERT INTO `tblpriority` (`priority`,`dispatch_interval_days`,`arrival_interval_days`,`display_duration`) VALUES ('Low',45,60,'6-8 Weeks');
INSERT INTO `tblpriority` (`priority`,`dispatch_interval_days`,`arrival_interval_days`,`display_duration`) VALUES ('Very High',25,40,'3 Weeks');
index.php(main file)
<?php
use Cosmo\DAL\Order;
$priority_list_data = new Order();
$priority_list = $priority_list_data->getPriorityList();
$priority_option = '<option value=""></option>';
if ($priority_list != false) {
for ($i = 0; $i < count($priority_list); $i++) {
$priority_option .= '<option value= "' . $priority_list[$i]['priority_id'] . '" >' . $priority_list[$i]['priority'] . '</option>';
}
}
?>
<div class="item text-center">
<blockquote>
<div class="row form-group">
<div class="col-md-2 col-sm-1"></div>
<div class="col-md-8 col-sm-10">
<div class="panel panel-default">
<div class="panel-body">
<span class="pull-left">Priority:</span>
<select class="form-control" id="priority_selected">
<?php echo $priority_option; ?>
</select>
<div class="small" id="priority_duration"></div>
</div>
</div>
</div>
<div class="col-md-2 col-sm-1">
</div>
</div>
<div class="row form-group">
<div class="col-md-2 col-sm-1"></div>
<div class="col-md-4 col-sm-5">
<div class="panel panel-default">
<div class="panel-heading">Estimated Dispatch Date:</div>
<div class="panel-body" id="dispatch_date">
<h3></h3>
</div>
</div>
</div>
<div class="col-md-4 col-sm-5">
<div class="panel panel-default">
<div class="panel-heading">Estimated Date of Arrival:</div>
<div class="panel-body" id="arrival_date">
<h3></h3>
</div>
</div>
</div>
<div class="col-md-2 col-sm-1"></div>
</div>
</blockquote>
</div>
<script>
$(document).ready(function () {
$("#priority_selected").change(function () {
var id = $(this).find(":selected").val();
var dataString = 'priority_id=' + id;
$.ajax({
url: '_getprioritydata.php',
dataType: "json",
data: dataString,
cache: false,
success: function (resultData) {
if (resultData['msg'] == 'Success') {
$("#priority_duration").html(resultData.display_duration);
$("#arrival_date").html(resultData.arrival_interval_dates);
$("#dispatch_date").html(resultData.dispatch_interval_dates);
} else if (resultData['msg'] == 'Failed') {
$("#priority_duration").html('');
$("#arrival_date").html('');
$("#dispatch_date").html('');
} else {
$("#priority_duration").html('');
$("#arrival_date").html('');
$("#dispatch_date").html('');
}
}
});
})
});
</script>
Order.php(class file)
<?php
namespace Cosmo\DAL;
Class Order
{
private $db;
public function __construct(){
$config = ConfigSettings::getInstance();
$this->db = DB::getInstance($config->getDatabaseServer(), $config->getDatabaseUsername(), $config->getDatabasePassword(), $config->getDatabaseName());
}
public function getPriorityList(){
$result = $this->db->query("SELECT priority,priority_id FROM tblpriority");
$priority_data = $result->fetchAllArray();
if(count($priority_data)!= 0){
return $priority_data;
}
else{
return false;
}
}
public function getDurationandDates($priority_id)
{
$result = $this->db->query("SELECT display_duration,dispatch_interval_days,arrival_interval_days FROM tblpriority WHERE priority_id='" . $priority_id . "'");
$priorityData = $result->fetchAll();
return $priorityData;
}
}
?>
_getprioritydata.php (json file)
<?php
use Cosmo\DAL\Order;
$response = [];
if (!empty($_REQUEST["priority_id"])) {
$priority_id = $_REQUEST['priority_id'];
$addPriority = new Order();
$priorityData = $addPriority->getDurationandDates($priority_id);
$response['display_duration'] = '';
$response['dispatch_interval_dates'] = '';
$response['arrival_interval_dates'] = '';
if (!empty($priorityData)) {
$curDate = date('d F Y');
$response['msg']= 'Success';
$response['display_duration'] = $priorityData[0]->display_duration;
$response['dispatch_interval_dates'] = date('d F Y', strtotime($curDate. " +{$priorityData[0]->dispatch_interval_days} days"));
$response['arrival_interval_dates'] = date('d F Y', strtotime($curDate. " +{$priorityData[0]->arrival_interval_days} days"));
}
}
else{
$response['msg']= 'Failed';
}
header('Content-Type: application/json');
echo json_encode($response);
exit;

Answer 1

In order to make one of the options selected by default you should include the selected attribute for that specific option:
<option selected="selected">Some option</option>
To clarify, you only need to put the selected attribute on the default option (Replace some condition with what you use to determine the default option):
$priority_list_data = new Order();
$priority_list = $priority_list_data->getPriorityList();
$priority_option = '';
if ($priority_list != false) {
for ($i = 0; $i < count($priority_list); $i++) {
if (<some condition>) {
$is_default = 'selected="selected"';
}
$priority_option .= '<option '. $is_default .' value= "' .
$priority_list[$i]['priority_id'] . '" >' . $priority_list[$i]['priority'] . '</option>';
}
}