How to report score to a custom LMS

I'm trying to report {score} and the other standard variables from the Quiz Results page to our custom LMS by posting to an api endpoint, can anyone help? I assume by adding an Execute JavaScript action to On Enter of the Quiz Results page, like this? 

var xhr = new XMLHttpRequest();
xhr.open("POST", endpoint, true);
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.send(JSON.stringify({
    score: 'score',
    accuracy: 'percent'
}));

I'm trying to use SCORM, is this how it usually works or is there another method for reporting? How is the user identification usually handled?