Javascript - using fetch api

const file = document.querySelector('#file')

function upload(file){
    fetch('https://www.example.com', { // // Your POST endpoint
        method: 'POST',
        headers: {
            "Content-Type": "image/png" //  specify your content type (json or text or imge - look at google how to specify your content according to your data type)
        },
        body: file // your file object to be passed
    })
    .then(response => console.log(response.json)) // if the response is json object
    .then(success => console.log(success)) // return success response if request is sucessfull
    .catch(error => console.log('An error occurred: ', error)) // listen for error occurring...
}

const startUpload = () => upload(file.files[0]);

file.addEventListener('change', startUpload, true);