摘要：
demon1 function test(){ console.log(b); //undefined if(a){ var b = 100; } console.log(b) ////undefined c = 234; console.log(c) //234 } var a; test(); 阅读全文
摘要：
手写Call Function.prototype.MyCall = function(context){ var context = context ?? window; let fnSymbol = Symbol(); context[fnSymbol] = this; const arg = 阅读全文