select dropdown value depending first dropdown value in codeigniter php - php

Question

This is my view file here i use 5 search field like product, group, branch, startdate and end date. All are placed in different table. Both were worked nicely and searched nicely but now i want some additional option that is when i select a particular branch in group field dynamically show values based on branch field value. Now it is showing whole data in db.
NOTE: i want this change appear when dropdown select.
<div class="row">
<div class="col-md-12">
<div class="tab-content">
<form method="get" id="frmSearchGroupPur" action="<?php echo
base_url('admin/group/listgroup'); ?>">
<div class="form-body">
<div class="row">
<div class="col-md-4">
<div class="form-group">
<label class="col-md-5 control-label"
style="text-align: left">Product</label>
<div class="col-md-7">
<?php
$product = array();
// if($data['products']){
// foreach ($data['products'] as
$p)
{
// $product[$p['id']] =
$p['name'];
// }
// }
echo form_dropdown('product', $product,
$data['product'], array('class' => 'form-control
select2','id'=>'product'));
?>
</div>
</div>
</div>
<div class="col-md-4">
<div class="form-group">
<label class="col-md-5 control-label"
style="text-align: left">Branch</label>
<div class="col-md-7">
<?php
$branch = array(NULL=>'Any');
if($data['branches']){
foreach ($data['branches'] as $w){
$branch[$w['id']] = $w['name'];
}
}
echo form_dropdown('branch', $branch,
$data['branch'], array('class' => 'form-control','id'=>'branch_dat'));
?>
</div>
</div>
</div>
<div class="col-md-4">
<div class="form-group">
<label class="col-md-5 control-label"
style="text-align: left">Group</label>
<div class="col-md-7">
<?php
$group = array(NULL=>'Any');
if($data['groups']){
foreach ($data['groups'] as $g){
$group[$g->id] = $g->name;
}
}
echo form_dropdown('group', $group,
$data['group'], array('class' => 'form-control'));
?>
</div>
</div>
</div>
</div><br/>
<div class="row">
<div class="col-md-4">
<div class="form-group">
<label class="col-md-5 control-label"
style="text-align: left">Purchase Date From</label>
<div class='input-group date col-md-7'
id='datetimepicker6'>
<?php echo
form_input('fromdate',$data['fromdate'],array('class' => 'form-
control','id'=>'fromdate')); ?>
<span class="input-group-addon">
<span class="glyphicon glyphicon-
calendar"></span>
</span>
</div>
</div>
</div>
<div class="col-md-4">
<div class="form-group">
<label class="col-md-5 control-label"
style="text-align: left">Purchase Date To</label>
<div class='input-group date col-md-7'
id='datetimepicker7'>
<?php echo
form_input('todate',$data['todate'],array('class' => 'form-
control','id'=>'todate')); ?>
<span class="input-group-addon">
<span class="glyphicon glyphicon-
calendar"></span>
</span>
</div>
</div>
</div>
</div><br/>
<div class="row">
<div class="col-md-4">
<div class="form-group pull-center">
<button type="submit" id="btnFilter" class="btn
btn-info">Submit</button>
<a href="<?php echo
base_url('admin/group/listgroup'); ?>" class="btn btn-default">Reset</a>
</div>
</div>
</div>
</div>
</form>
</div>
</div>
and my model file to get group is
function getGroupDetails($groupid=0,$state=''){
$this->db->where('id',$groupid);
$this->db->where('branchid',$state);
$query = $this->db->get('group');
if($query->num_rows()==1){
return $query->row_array();
}else{
return FALSE;
}
and my controller function is
function get_group(){
$state=$this->input->post('brch');
$result = $this->model_group->getGroupDetails($state);
// echo json_decode($result);
}
and my not worked jquery file to change group dynamically is below
$('branch_dat').change(function(){
var branch_da=$('#branch_dat').val();
if(branch_da != "")
{
var post_url="admin/sale/get_group";
$('branch_dat').change(function(){
var branch_da=$('#branch_dat').val();
if(branch_da != "")
{
var post_url="admin/sale/get_group";
$.ajax({
type:"POST",
url:post_url,
data:function(params)
{
return{ brch : params.brch};
}
});
}
});