JS中各種變數型別在條件判斷為false的情況
阿新 • • 發佈:2018-11-04
var a = undefined; ->false
var a = 0; ->false
var a = 0.0; ->false
var a = NaN; ->false
var a = ""; ->false
var a = null; ->false
var a = false; ->false
var a ->false
function a(){
};
//呼叫無返回值的函式,預設返回值是undefined
a() ->false