Javascript Application

I have a Javascript application that defines a product using drag and drop. I need a program written that gets executed after the drag and drop application has completed that combines AutoCAD DXF files and modifies others depending upon the results of the original drag and drop application. Website: [login to view URL] I will provide a DXF for the original image displayed and each of the individual drag and drop elements. When an element is dragged and dropped, we need to copy the DXF file into the original DXF file to show the modification. However, the elements DXF file must be modified with the correct X, Y location to be viewed correctly in a DXF viewer. The final result should be a file that is downloadable by the end user using any/all major browsers.