Cannot Retrieve Javascript this object onChange Event

[aboah]

We are unable to retrieve the Javascript this object onChange Event.
How can this solved
$('#chosePicture').filestyle({
placeholder: "Please Choose a file",
buttonText: 'Select File',
'onChange': function (files) {

    console.log("filestyle this Javascript", this);
    console.log("filestyle files", files[0]);
}

});