// 考題二,考變量提升和沒有塊級作用域: console.log(a); if ('a' in window) { var a = 10; } console.log(a); // 考題三,考函數作用域: if ('a' in window) { (function(){ var a = 10; }()); } console.log(a);
預解析和作用域問題
慕斯709654
2018-08-06 14:14:04