Uploading XML files on ODK aggregate on iOS
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I have an android application which works with ODK Aggregate. Application makes an xml file based on users inputs on xforms and uploads it on ODK server by ODK data collector.
The task is make this application compatible with Android, iOS devices and windows mobiles. 

Since ODK is just implemented for android, we should find a way to upload xml file on ODK server by HTML5 or any other programming language, to make it a cross platform.
I know HTML5 might be answer but I'm lost on it and don't know where exactly I should look for possible solution.
Any kind of helps would be helpful.