Unique Reference Number

Higher Education Statistics Agency. [1 March 2020].  UCF celebrates record number of graduates. University College Falmouth. [2008-03-19]. （原始内容存档于2011-09-29）

ISBN 0-12-017641-6.  Warren et.al. Genome analysis of the platypus reveals unique signatures of evolution (PDF). Nature. 2008, 453 (7192) [2012-05-03]. PMC 2803040 

Guide 2023. The Times. 2022-09-17.  UWL News. University of West London number one in London for student satisfaction | University of West London. www

9780416417500; OCLC 12582178（页面存档备份，存于互联网档案馆） 括號內包含屬地與爭議國家A number in parentheses indicates the number of unique sovereign states that the country or territory shares

} // ... 或第三个 调用isUndefined(my_var)会抛出ReferenceError，如果my_var是未知标识符，但typeof my_var === 'undefined'不会抛出异常。 Number数据类型表示IEEE-754浮点双精度。不能精确表示一些实数或分数。如： console