Function assert

notes/docsify/unpkg/gotop/jquery-2.1.0.js:875–890

* Support testing using an element * @param {Function} fn Passed the created div and expects a boolean result

( fn )

 * @param {Function} fn Passed the created div and expects a boolean result
 */
function assert( fn ) {
	var div = document.createElement("div");

	try {
		return !!fn( div );
	} catch (e) {
		return false;
	} finally {
		// Remove from its parent by default
		if ( div.parentNode ) {
			div.parentNode.removeChild( div );
		}
		// release memory in IE
		div = null;
	}
}

/**
 * Adds the same handler for all of the specified attrs