This has nothing to do with the Evenbrite javascript API. The layout is determined by the markup and css styling of your page. The eventList
method returns HTML, so you can put that into a specific element and style it appropriately. For example:
<head>
<script>
$(document).ready(function(){
Eventbrite({'app_key': $APP_KEY}, function(eb){
eb.organizer_list_events( {'id': 561037966, 'statuses': "live,started"}, function( response ){
var event_list_html = eb.utils.eventList( response, eb.utils.eventListRow );
$("#event-list").html(event_list_html);
});
});
});
</script>
<style>
#event-list {
width: 400px;
border: 1px solid black;
}
</style>
</head>
<body>
<div id="event-list"></div>
</body>