What is the debounce function in JavaScript

Question

The JavaScript "debouncing" feature piques my attention.

Unfortunately, the code is not presented in a way that I can comprehend. 

How does it function (my comments are below)? I just do not understand how this works, to put it briefly.

   // Returns a function, that, as long as it continues to be invoked, will not
   // be triggered. The function will be called after it stops being called for
   // N milliseconds.


function debounce(func, wait, immediate) {
    var timeout;
    return function() {
        var context = this, args = arguments;
        var later = function() {
            timeout = null;
            if (!immediate) func.apply(context, args);
        };
        var callNow = immediate && !timeout;
        clearTimeout(timeout);
        timeout = setTimeout(later, wait);
        if (callNow) func.apply(context, args);
    };
};