elgg_extract($key, $array, $default=null, $strict=true)
Checks for $array[$key] and returns its value if it exists, else returns $default.
define(function(require){var $=require('jquery');$(document).on('change', '#elgg-river-selector', function(){var url=window.location.href;if(window.location.search.length){url=url.substring(0, url.indexOf('?'));}url+= '?'+$(this).val();window.location.href=url;});})
Initiates page reload when river selector value changes core/river/filter.