* 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

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

* Check for string * @param {Object} s

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