* Displays an alert. * @param {String} str String to display.

* Extend a prototyped class by new members * @param {Object} parent * @param {Object} members

* Check for object * @param {Object} obj

获得下一个ID (该方法是线程安全的) @return SnowflakeId

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

* Fix JS round off float errors * @param {Number} num

* Discard an element by moving it to the bin and delete * @param {Object} The HTML node to discard

* Remove last occurence of an item from an array * @param {Array} arr * @param {Mixed} item

* Check for string * @param {Object} s

* Check if an element is an array, and if not, make it into an array. Like * MooTools' $.splat.

* Provide error messages for debugging, with links to online explanation

* Mark a function for special use by Sizzle * @param {Function} fn The function to mark