JS——坑9

var a = 1;
		function test(){
			//变量提前到这里 var a;
			//var a;
			console.log(a);
			var a = 1;
		}
		test(); //undefined

c = 5;
		function test3(){
			window.c = 3;
			console.log(c);//undefined  因为var c会提前，而且这里会输出局部c
			var c;
			console.log(window.c);//3
		}
		test3();