摘要:
forEach() 阅读全文
posted @ 2018-05-19 10:51
杨不凡
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摘要:
typeof 运算符把类型信息当作字符串返回。typeof 返回值有六种可能: "number," "string," "boolean," "object," "function," 和 "undefined."我们可以使用typeof来获取一个变量是否存在,如if(typeof a!="unde 阅读全文
posted @ 2018-05-19 10:17
杨不凡
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