Post request works fine in Postman and Insomnia, but not in JS code

Question

I've been trying to get this post request to work for a few days now, but it doesn't matter what I change, it never works. This is the JS code that I'm using:

axios({
    method: 'POST',
    url: "https://[DOMAIN]/datanew.php?sto=0",
    data: {
        aktion:"getstdpl",
        sid:0,
        ignore:1
    },
    headers: {
        "Cookie": "PHPSESSID=ad4aaf7f7a5...",
        "Content-Type": "multipart/form-data"
    },
})
.then(data => {
    console.log(data.data)
    //console.log(data)
})
.catch(err => console.log(err));

I have tried the same request in both Insomnia and Postman and it works fine in both, but using my provided JS code, I just get no output at all. Not even an error. After failing to get a satisfying result in JS I also tried to use Java, but that gave me the same result as JS.

Answer 1

Browsers are limited by Same Origin Policy in what they can read or write. In particular, browsers' code loaded from one origin is not allowed to set cookies designated for another origin.