JavaScript中的枚举
2010-09-14 13:42:49 来源:WEB开发网本文示例源代码或素材下载
在JavaScript目前的版本中,没有枚举这个概念(当然,ECMA-262第三版中已经将enum作为关键字保留)。然而,如同JavaScript中没有class一样,但我们仍然可以通过间接的方式——JSON来实现它。
如下,我们来定义Week的枚举:
if(typeof WeekDay == "undefined"){
var WeekDay = {};
WeekDay.Sunday = 0;
WeekDay.Monday = 1;
WeekDay.Tuesday = 2;
WeekDay.Wedesay = 3;
WeekDay.Thursday = 4;
WeekDay.Friday = 5;
WeekDay.Saturday = 6;
}
测试如下:
alert(WeekDay.Monday); // -----> Output: 1
当然,我们有更为直观的方式。以定义DOM文档节点类型为例,定义方式如下:
if(typeof Node == "undefined"){
var Node = {
ELEMENT_NODE: 1,
ATTRIBUTE_NODE: 2,
TEXT_NODE: 3,
CDATA_SECTION_NODE: 4,
ENTITY_REFERENCE_NODE: 5,
ENTITY_NODE: 6,
PROCESSING_INSTRUCTION_NODE: 7,
COMMENT_NODE: 8,
DOCUMENT_NODE: 9,
DOCUMENT_TYPE_NODE: 10,
DOCUMENT_FRAGEMENT_NODE: 11,
NOTATION_NODE: 12
}
}
Tags:JavaScript 枚举
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