$.isPlainObject

$.isPlainObject(object) ⇒ boolean

True if the object is a "plain" JavaScript object, which is only true for object literals and objects created with new Object.

$.isPlainObject({})         // => true
$.isPlainObject(new Object) // => true
$.isPlainObject(new Date)   // => false
$.isPlainObject(window)     // => false