Upload file with jquery and formdata (untested, should work)

gistfile1.js

/**
 * Shows Filepicker dialog and uploads the chosen file to the given url
 * 
 * @param url URL where the file is sent
 * @param successHandler Success callback function
 * @param errorHandler Error callback function
 * @see https://developer.mozilla.org/en-US/docs/Web/API/FormData
 */
function uploadFile(url, successHandler, progressHandler, errorHandler) {
	var $fileInput = $('<input type=file>');
	
	$fileInput.change(function(){
		var fd = new FormData();
		var file = this.files[0];
		
		fd.append('file', file);
		
	    $.ajax({
	        url: url,
	        type: "POST",
	        data: fd,
	        processData: false,
	        contentType: false,
	        success: function(response) {
	        	successHandler(response);
	        },
	        error: function(jqXHR, textStatus, errorMessage) {
	        	errorHandler(jqXHR, textStatus, errorMessage);
	        },
	        xhr: function() {
	        	var req = new window.XMLHttpRequest();
	        	
	        	req.upload.addEventListener("progress", function(e) {
	        		progressHandler(e);
	            	if(e.lengthComputable) {
	            		progressHandler(((100*e.loaded/e.total).toPrecision(3)));
	            	}
	            }, false);
	        	
	            return req;
	        }
	    });
	});

	$fileInput.click();
}