Is there a way to increment custom HTML attributes?

I'm building something using dynamic fields and I want to be able to number each field so I can use POST requests.

Is there a way that I can increment custom attributes so I know which field is which?

var qID = 0;

<div class="questionContainer" data-question-id="qID"></div>

qID++;

I've tried this but it just converts the attribute into a string. Thanks!