Returning multiple json objects with one php function

Question

I am trying to populate two dropdown menu whose value is dependent with other one. In total I have 3 dropdowns. one for selecting a class and other two for selecting the subjects and exams of selected class. I can populate one drop down menu (say for eg: select subject). but how can i populate both of them. My code is as follows:

 <table>
 <tr>
 <td> select class</td>
 </tr>
 <tr>
 <td> select subject</td>
 </tr>
 <tr>
 <td> select exam</td>
 </tr>
 <tr>
 <td><select class="form-control m-bot15" name="class_id" value='' onchange="myFunction(this)" style="float:left;" id="carId">
 <option value="">select a class</option>
 <option value="1">One</option>
 <option value="2">Two</option>
 <option value="3">Three</option>
 </select></td>
 </tr>
 <tr>
 <td><select class="form-control m-bot15" name="subject_id" value='' style="float:left;" id="emptyDropdown">
 <option value="">select a subject</option>
 </select></td>
 <tr>
 </tr>
 <td><select class="form-control m-bot15" name="exam_id" value='' style="float:left;" id="emptyDropdown2">
 <option value="">select a subject</option>
 </select></td>
 </tr>
 </table>

This is my view function My script for populating subject name is :

 <script>
 function myFunction(obj)
 {
 $('#emptyDropdown').empty()
 var dropDown = document.getElementById("carId");
 var carId = dropDown.options[dropDown.selectedIndex].value;
 $.ajax({
 type: "POST",
 dataType: 'json',
 url: "<?php echo base_url();?>mark/newdrp",
 data: { 'carId': carId },
 success: function(data){
 $.each(data, function () {
 $('#emptyDropdown').append('<option value='+this.subject_id+'>' + this.name + '</option>');
 });
 }
 });
 }
 </script>

My controller function newdrp is

 public function newdrp(){
 $classId = $this->input->post('carId');
 $subjects = $this->subject_model->Subjectbyclassid($classId);
 echo json_encode($exams);
 }

This works fine. Iam getting the subjects list in my dropdown. But i want to pass one more json object like this

 public function newdrp(){
 $classId = $this->input->post('carId');
 $subjects = $this->subject_model->Subjectbyclassid($classId);
 $exams = $this->exam_model->Exambyclassid($classId);
 echo json_encode(array($subjects,$exams));
 }

This is my console preview

 [[{"subject_id":"1","name":"Physics","class_id":"1","teacher_id":null},{"subject_id":"2","name":"Chemistry","class_id":"1","teacher_id":null},{"subject_id":"3","name":"Mathematics","class_id":"1","teacher_id":null}],[{"exam_id":"22","name":"BW9","date":"03\/10\/16","class_id":"1","comment":""},{"exam_id":"26","name":"BW10","date":"17\/10\/16","class_id":"1","comment":""},{"exam_id":"30","name":"BW11","date":"31\/10\/16","class_id":"1","comment":""},{"exam_id":"34","name":"BW12","date":"14\/11\/16","class_id":"1","comment":""},{"exam_id":"40","name":"BW13","date":"28\/11\/16","class_id":"1","comment":""},{"exam_id":"45","name":"BW14","date":"11\/12\/16","class_id":"1","comment":""},{"exam_id":"46","name":"Revision Exam 1","date":"02\/01\/17","class_id":"1","comment":""},{"exam_id":"49","name":"Revision Exam 2","date":"8\/01\/2017","class_id":"1","comment":""},{"exam_id":"51","name":"Revision Exam 3","date":"15\/01\/17","class_id":"1","comment":""},{"exam_id":"55","name":"Revision Exam 4","date":"22\/01\/17","class_id":"1","comment":""},{"exam_id":"57","name":"Revision exam 5","date":"26\/01\/2017","class_id":"1","comment":""},{"exam_id":"59","name":"Revision Exam 6","date":"29\/01\/17","class_id":"1","comment":""}]]

How can i loop through this an display the exam name in corresponding dropdown. Please help

Answer 1

You'll have to loop through the second array as well, data being the parent array

success: function(data){
 var examArr = data[1];
 $.each(examArr, function () {
 $('#emptyDropdown2').append("<option value='" + $(this).exam_id + "'>" + $(this).name + "</option>");
 });
 }

• Dan Philip Bejoy: Happy to help !