单项选择题
A.undefined
B.null
C.Something
D.smtg
单项选择题 function foo() { let a; window.b = 0; a = window.b; a++; return a; } foo(); typeof a; typeof window.b; ()
单项选择题 const length = 4; const numbers = []; var i; for (i = 0; i < length; i++) { // does nothing } { // a simple block numbers.push(i + 1); } console.log(numbers)结果为? ()
单项选择题 function arrayFromValue(items) { return; [items]; } arrayFromValue(10) ()