How this code alert 1.

Question

function func(n) {
if(n<=1) {
return 1;
} else {
return func(n-1);
}
}
alert(func(4));

Answer 1

1st call:
n = 4;
if = false; else = true

else returns func(4 - 1) // n = 3

2nd call by else:
n = 3;
if false; else = true

else return func(3 - 1) // n = 2

3rd call by else:
n = 2;
if false; else true

else return func(2 - 1) // n = 1

4th call by else:
n = 1;
if true; else = false

if returns 1 // no more func() calls by else, code stops

Answer 2

Because you told it to do so
...return 1;

if you say "return 100;"
100 will be the output.

try this...

var n;
function func(n) {
if(n<=1) {
return n;
} else {
return func(n-1);
}
}
alert(func(parseInt(prompt())));

with the above code, every input will give "1"
since it returns the final value of n as @Ben Bright explained

Answer 3

thanks brother for clear this misunderstand.