How to get the multiple selected data on isteven multi select angular js?

Question

HTML for isteven multi select (Selecting Social media and job boards) is shown in the following image

As you can see i'm using isteven multi select for my view in my website.

These are the Get function in my controllers to get the data's needed in the input and output model that is shown below

What i wanted to do now is when they select 2 or more than choices in the isteven multi select box i can get those data! But want i want is only the PK's from those choices

Well i tried and this is my code for that matter

$scope.form.social_media = $scope.jobrequest.social_media[0].pk;

But as you can see i can only get one pk and that pk is the first one the user selected in the isteven multi select box. Do you guys have any suggestions regarding this problem?

Please provide a Minimal, Complete, and Verifiable example of your attempt, so we can try to solve your problem and explain why your own attempt failed - that way you can learn something useful for your future development, as well as getting an answer to this single problem. — SAMUEL
Add .data on output-model. eg. output-model="dropdownoutput.data" — Malik Zahid