Function isExtensible

object.js:331–344

(object)

	}

	function isExtensible (object) {
		var prop = '_poly_';
		try {
			// create unique property name
			while (prop in object) prop += '_';
			// try to set it
			object[prop] = 1;
			return hasProp(object, prop);
		}
		catch (ex) { return false; }
		finally {
			try { delete object[prop]; } catch (ex) { /* squelch */ }
		}
	}

	function preventExtensions (object) {
		return object;