y = (++x, ++x);
console.log(y);
y=3
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js 基本類型
boolean, number, string, undefined
null is object
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js一些預設方法
string.slice(s, e), array.slice(s, e) => slice(切片)
string.split(符號) 分割成 array => split (分裂)
array.splice(s, l, data_1, data_2)=>splice (拼接)
string.match() => //正則是否用/g差別很大,/g將不顯示捕獲組,但會將符合的化為 array
regular.exec()