单项选择题
var hel="hello"; (function(){ var word="World"; console.log(hel+word); })();以上代码最后一次打印的结果是( )
A.helloWorld B.undefined C.程序报错bar is not defined D.null
foo(); function foo(){ console.log(a); var a=2; }描述错误的是...
foo(); function foo(){ console.log(a); var a=2; }描述错误的是()
A.foo函数存在函数提升 B.在函数内部的a变量存在变量提升 C.打印的结果是2 D.打印的结果是undefined
function test() { console.log(a); console.log(fun()); v...
function test() { console.log(a); console.log(fun()); var a = 1; function fun() { return 2; } } test();结果是()
A.undefined 2 B.2 undefined C.undefined D.2
(function() { console.log(3); setTimeout(function(){con...
(function() { console.log(3); setTimeout(function(){console.log(2)}, 2000); setTimeout(function(){console.log(1)}, 0); console.log(4); })();打印的结果是()
A.1 2 3 4 B.2 1 3 4 C.4 3 1 2 D.3 4 1 2