问XMLHttpRequest邮政

EN

    xhr = new XMLHttpRequest();

                // Update progress bar etc
                xhr.upload.addEventListener("progress", function(evt) {
    if (evt.lengthComputable) {
    progressBar.style.width = (evt.loaded / evt.total) * 100 + "%";
    }
    else {
    // No data to calculate on
    }
    }, false);

    // File uploaded
    xhr.addEventListener("load", function() {
    progressBarContainer.className += " uploaded";
    progressBar.innerHTML = "Uploaded!";
    }, false);

    xhr.open("post", "imageSave.aspx", true);

    // Set appropriate headers
               xhr.setRequestHeader("Content-Type", "multipart/form-data");
       xhr.setRequestHeader("X-File-Name", file.fileName);
       xhr.setRequestHeader("X-File-Size", file.fileSize);
       xhr.setRequestHeader("X-File-Type", file.type);

       // Send the file
       xhr.send(file);