Red John has committed another murder. But this time, he doesn't leave a red smiley behind. What he leaves behind is a puzzle for Patrick Jane to solve. He also texts Teresa Lisbon that if Patrick is successful, he will turn himself in. The puzzle be…
数据类型:JavaScript定义的数据类型有字符串.数字.布尔.数组.对象.Null.Undefined,但typeof有区分可判别的数据分类是number.string.boolean.object(null / array).function和undefined.undefined 这个值表示变量不含有值,null 可以用来清空变量 let a = 100; typeof a;//number a = undefined; typeof a;//undefined a = null; ty…