index.php

$("#my-awesome-dropzone").dropzone({
	url: "upload-files.php", 
	maxFilesize: 2,
	acceptedFiles: ".txt",
	sending: function (file, xhr, formData) {
		var sider = $("#side").val();
		var deckName = $("#deckname").val();
		formData.append("filename", deckName);
		formData.append("side", sider);
	},
	success: function( something, data ) {
	window.open( data );
}
});