You are developing a web page that enables customers to upload documents to a web server.
The page includes an HTML5 PROGRESS element named progressBar that displays information about the status of the upload.
The page includes the following code. (Line numbersare included for reference only.)
An event handler must be attached to the request object to update the PROGRESS element on the page.
You need to ensure that the status of the upload isdisplayed in the progress bar.
Which line of code should you insert at line 03?
A.
xhr.upload.onloadeddata =
B.
xhr.upload.onplaying =
C.
xhr.upload.onseeking =
D.
xhr.upload.onprogress =
D onprogress
http://stackoverflow.com/questions/15965651/progress-bar-while-uploading-large-files-with-xmlhttprequest
D. onprogress
The following event handlers are supported for XMLHttpRequest and XMLHttpRequestUpload objects:
onloadstart – the request starts
onprogress – transmitting data
onabort – request has been aborted
onerror – the request has failed
onload – the request has successfully completed
ontimeout – the timeout has passed before the request completed
onloadend – the request has completed