从Brightspace上的API获取字段

I have a function that get all data from the api classlist and show it in json format. However, I want to return only the OrgDefinedId. How could I do that? Here is my function. I am using JS and php.

function getClasslist(){
  hideData();
  document.getElementById("GETField").checked = true;
  document.getElementById("actionField").value = "/d2l/api/bas/1.0/orgunits/167877/classlist/";

}