In WebKit, XMLHttpRequest.send() supports sending single file. It would be better if we can support sending multiple files, like FileList (see bug 25923 <https://bugs.webkit.org/show_bug.cgi?id=25923>). In addition, XMLHttpRequest.send() only sends the raw content of the file, without including the multipart boundary separators (see bug 26979<https://bugs.webkit.org/show_bug.cgi?id=26979> ). To resolve these issues, we can enhance XMLHttpRequest.send() to support a FileList object and add multipart boundary separators support. Or, the other simpler way (thanks for suggestion from Darin Fisher) is to extend XMLHttpRequest.send() to take an array of items. Each of item could either be a string or a file reference. The web application is responsible to generate the miultipart enevelop like the following: var payload = new Array; payload.push(header1); payload.push(file1); payload.push(footer1); ... xhr.send(payload); How do you guys think about these approaches? Thanks, Jian