JavaScript select menu on change for WordPress post filtering

JS: WordPress select menu filtering

$('select[name="post_date"]').on('change', function() {

	var postDate = this.options[this.selectedIndex].value,
			dateRE = /\d{4}[-]\d{1,2}|\d{4}/g,
			prevDate = dateRE.exec(url);

	// Drop pagination when changing the post_date filter value
	if (url.indexOf('page/') > 0)
		url = url.split('page/')[0];

	// If a date exists in URL already, drop it and go to new date,
	// otherwise go directly to the date specified
	window.location = (prevDate) ? url.split(prevDate[0])[0] + postDate + '/' :  url + postDate + '/';

});