How can I upload blob data to vault in javascript?

Thank you. I solved the problem thanks to you.

I made a html component in form like below.

When copy and paste an image from clipboard, it will be uploaded in vault.

and the uploaded file will be Item's image property. 

    <div>

        <img src="" id="pastedImage">

    </div>

    <script>

            document.onpaste = function(event) {

                var items = event.clipboardData.items;

                console.log(JSON.stringify(items)); // will give you the mime types

                var blob = items[0].getAsFile();

                var reader = new FileReader();

                reader.onload = function(event) {

                    console.log(event.target.result);

                    document.querySelector('#pastedImage').src = event.target.result;

                    var file = new File([blob],'test.png',{type:"image/png"});

                    var newFile = aras.newFileItem(file);

                    var fileId = newFile.getAttribute("id");

                    var fileItem = aras.IomInnovator.newItem();

                    fileItem.loadAML(newFile.xml);

                    fileItem = fileItem.apply();

                    window.handleItemChange("_paste_image","vault:///?fileId="+fileId);       

                }; // data url 

                reader.readAsDataURL(blob);

            }

    </script>