JavaScript下标的相关内容

文章 2017-12-16 来自：开发者社区

JS编程建议——55：不要拘泥于数字下标

建议55：不要拘泥于数字下标数组下标默认为大于或等于0的整数，不过JavaScript允许数组下标可以为任意表达式，甚至为任意类型数据。（1）文本下标为数组下标指定负值：var a = []; // 定义空数组直接量a[-1] = 1; // 为下标为-1的元素赋值很显然，上面的用法是非法的，因为这不符合语法规范。使用length属性检测，返回值为0，说明数组并没有增加长度，这是正确的，也很正.....

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