src/modules/mousewheel/index.js
function(elem, listener) {
        var normalizedListener = function(e) {
            listener(normalizeWheelEvent(e));
        };

        EVENT_NAMES.forEach(function(name) {
            elem.addEventListener(name, normalizedListener);
        });

        return function() {
            EVENT_NAMES.forEach(function(name) {
                elem.removeEventListener(name, normalizedListener);
            });
        };

    }
function(elem, listener) {
        var normalizedListener = function(e) {
            listener(normalizeWheelEvent(e));
        };

        EVENT_NAMES.forEach(function(name) {
            elem.addEventListener(name, normalizedListener);
        });

        return function() {
            EVENT_NAMES.forEach(function(name) {
                elem.removeEventListener(name, normalizedListener);
            });
        };

    }
function ( elem , listener ) { var normalizedListener = function ( e ) { listener ( normalizeWheelEvent ( e ) ) ; } ; EVENT_NAMES . forEach ( function ( name ) { elem . addEventListener ( name , normalizedListener ) ; } ) ; return function ( ) { EVENT_NAMES . forEach ( function ( name ) { elem . removeEventListener ( name , normalizedListener ) ; } ) ; } ; }
binds a cross browser normalized mousewheel event, and returns a function that will unbind the listener;
binds a cross browser normalized mousewheel event and returns a function that will unbind the listener ;