JS function to get or set a cookie

doCookie.js

/**
 * doCookie: function to get or set a cookie
 * @param name (string): cookie name
 * @param value (string - optional): cookie value to set
 * @param options (object - optional): possible options are
 *  - expires: (number of days | proper datetime string)
 *  - path: (string)
 *  - domain: (string)
 */
function doCookie(name, value, options) {
	var expires = '', date, path, domain, cookieValue = null, cookie, cookies, i;
	if (typeof value !== 'undefined') {
		/* value provided, set cookie */
		options = options || {};
		if (value === null) {
			value = '';
			options.expires = -1;
		}
		if (options.expires && (typeof options.expires === 'number' || options.expires.toUTCString)) {
			if (typeof options.expires === 'number') {
				date = new Date();
				date.setTime(date.getTime() + (options.expires * 24 * 60 * 60 * 1000));
			} else {
				date = options.expires;
			}
			expires = '; expires=' + date.toUTCString();
		}
		path = options.path ? '; path=' + (options.path) : '';
		domain = options.domain ? '; domain=' + (options.domain) : '';
		document.cookie = [name, '=', encodeURIComponent(value), expires, path, domain].join('');
	} else {
		/* no value, get cookie */
		if (document.cookie && document.cookie !== '') {
			cookies = document.cookie.split(';');
			for (i = 0; i < cookies.length; i += 1) {
				// trim value
				cookie = cookies[i].replace(/^[\s]+/, '').replace(/[\s]+$/, '');
				if (cookie.indexOf(name + '=') === 0) {
					cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
					break;
				}
			}
		}
		return cookieValue;
	}
}