Question

var arrayfunc = [function(){return this;}];
var func = arrayfunc[0];
arrayfunc[0]();    //[function (){return this;}]
func();            //Window

i don’t know why this is not same? Do you help me ?

Answer 1

Just think as below:

arrayfunc[0](); // this refer to arrayfunc
window['func'](); // this refer to window

Even through arrayfunc[0] === func return true, the caller is different.

arrayfunc[0](); called the function through the object arrayfunc,

window['func'](); called the function through the object window.