Why I got different result when using different `for loop` in javascript?

Question

I have a question about for loop in js, here are examples:

In this part, child is object (what I want).

for (var i = 0; i < element.childNodes.length; i++) {
        var child = element.childNodes[i];
        console.log(typeof(child));
}

But when change the code, child become to String, valued 0, 1, 2 ...

for (var child in element.childNodes) {
        console.log(typeof(child));
}

Why the two types of for loop got different results? Thanks..

the second loop is looping through the keys. To obtain similar result you would need `element.childNodes[child]` — maioman, Oct 09 '17 at 14:34
because the `for..in` loop iterates the enumerable keys of an object. Like `for(var key in object) ...`. you probably meant `for(var child of element.childNodes) ...` — Thomas, Oct 09 '17 at 14:34
Why did you not use the `for (var i in element.childNodes) { var child = element.childNodes[i]; … }` pattern in the second snippet as well? — Bergi, Oct 09 '17 at 14:43

score 0 · Answer 1 · answered Oct 09 '17 at 14:42

0

Said properties are just strings which i believe are the keys in your object.

answered Oct 09 '17 at 14:42

davidchoo12

score -1 · Answer 2 · answered Oct 09 '17 at 14:35

-1

In a for in loop, you retrieve keys. The following should log the same as your first loop:

for (var child in element.childNodes) {
  console.log(typeof(element.childNodes[child]));
}

answered Oct 09 '17 at 14:35

Meldon

2 Answers2