Front-end learning of the sixth bullet: functions and closures in JavaScript

Front-end learning of the sixth bullet: functions and closures in JavaScript

When function is nested within function, internal function can access variables in external function

function foo (x) {
var tmp = 3;
function Bar (y) {
Alert (x + y + (++tmp));
}
Bar (10);
}
Foo (2)

At this point, no matter how the output is 16, but this is not a closure

If we return an intrinsic function, internal functions will close-over the variables of the external function until the internal functional end

functionfoo (x) {  var tmp = 3;
    return  Function  (y) {
        alert (X + y  +  (++tmp));
   }
}
Var bar = foo (2);  // bar is now a closure
bar; this time the repeated operation will output 16,17,18 ...This is a closure .

Front-end learning of the sixth bullet: functions and closures in JavaScript