function file__get_ext(fname){
        //calculating extension
        dotpos = fname.lastIndexOf('.');
        return fname.substring(dotpos + 1, fname.length);
    }
    
    function file__get_mime_type(fname){
        var ext = file__get_ext(fname);
        if(!ext) return false;
        switch(ext){
            case 'ai' : return  'application/postscript';
            case 'aif' : return  'audio/x-aiff';
            case 'aifc' : return  'audio/x-aiff';
            case 'aiff' : return  'audio/x-aiff';
            case 'asc' : return  'text/plain';
            case 'au' : return  'audio/basic';
            case 'avi' : return  'video/x-msvideo';
            case 'bcpio' : return  'application/x-bcpio';
            case 'bin' : return  'application/octet-stream';
            case 'c' : return  'text/plain';
            case 'cc' : return  'text/plain';
            case 'ccad' : return  'application/clariscad';
            case 'cdf' : return  'application/x-netcdf';
            case 'class' : return  'application/octet-stream';
            case 'cpio' : return  'application/x-cpio';
            case 'cpt' : return  'application/mac-compactpro';
            case 'csh' : return  'application/x-csh';
            case 'css' : return  'text/css';
            case 'dcr' : return  'application/x-director';
            case 'dir' : return  'application/x-director';
            case 'dms' : return  'application/octet-stream';
            case 'doc' : return  'application/msword';
            case 'drw' : return  'application/drafting';
            case 'dvi' : return  'application/x-dvi';
            case 'dwg' : return  'application/acad';
            case 'dxf' : return  'application/dxf';
            case 'dxr' : return  'application/x-director';
            case 'eps' : return  'application/postscript';
            case 'etx' : return  'text/x-setext';
            case 'exe' : return  'application/octet-stream';
            case 'ez' : return  'application/andrew-inset';
            case 'f' : return  'text/plain';
            case 'f90' : return  'text/plain';
            case 'fli' : return  'video/x-fli';
            case 'gif' : return  'image/gif';
            case 'gtar' : return  'application/x-gtar';
            case 'gz' : return  'application/x-gzip';
            case 'h' : return  'text/plain';
            case 'hdf' : return  'application/x-hdf';
            case 'hh' : return  'text/plain';
            case 'hqx' : return  'application/mac-binhex40';
            case 'htm' : return  'text/html';
            case 'html' : return  'text/html';
            case 'ice' : return  'x-conference/x-cooltalk';
            case 'ief' : return  'image/ief';
            case 'iges' : return  'model/iges';
            case 'igs' : return  'model/iges';
            case 'ips' : return  'application/x-ipscript';
            case 'ipx' : return  'application/x-ipix';
            case 'jpe' : return  'image/jpeg';
            case 'jpeg' : return  'image/jpeg';
            case 'jpg' : return  'image/jpeg';
            case 'js' : return  'application/x-javascript';
            case 'kar' : return  'audio/midi';
            case 'latex' : return  'application/x-latex';
            case 'lha' : return  'application/octet-stream';
            case 'lsp' : return  'application/x-lisp';
            case 'lzh' : return  'application/octet-stream';
            case 'm' : return  'text/plain';
            case 'man' : return  'application/x-troff-man';
            case 'me' : return  'application/x-troff-me';
            case 'mesh' : return  'model/mesh';
            case 'mid' : return  'audio/midi';
            case 'midi' : return  'audio/midi';
            case 'mif' : return  'application/vnd.mif';
            case 'mime' : return  'www/mime';
            case 'mov' : return  'video/quicktime';
            case 'movie' : return  'video/x-sgi-movie';
            case 'mp2' : return  'audio/mpeg';
            case 'mp3' : return  'audio/mpeg';
            case 'mpe' : return  'video/mpeg';
            case 'mpeg' : return  'video/mpeg';
            case 'mpg' : return  'video/mpeg';
            case 'mpga' : return  'audio/mpeg';
            case 'ms' : return  'application/x-troff-ms';
            case 'msh' : return  'model/mesh';
            case 'nc' : return  'application/x-netcdf';
            case 'oda' : return  'application/oda';
            case 'pbm' : return  'image/x-portable-bitmap';
            case 'pdb' : return  'chemical/x-pdb';
            case 'pdf' : return  'application/pdf';
            case 'pgm' : return  'image/x-portable-graymap';
            case 'pgn' : return  'application/x-chess-pgn';
            case 'png' : return  'image/png';
            case 'pnm' : return  'image/x-portable-anymap';
            case 'pot' : return  'application/mspowerpoint';
            case 'ppm' : return  'image/x-portable-pixmap';
            case 'pps' : return  'application/mspowerpoint';
            case 'ppt' : return  'application/mspowerpoint';
            case 'ppz' : return  'application/mspowerpoint';
            case 'pre' : return  'application/x-freelance';
            case 'prt' : return  'application/pro_eng';
            case 'ps' : return  'application/postscript';
            case 'qt' : return  'video/quicktime';
            case 'ra' : return  'audio/x-realaudio';
            case 'ram' : return  'audio/x-pn-realaudio';
            case 'ras' : return  'image/cmu-raster';
            case 'rgb' : return  'image/x-rgb';
            case 'rm' : return  'audio/x-pn-realaudio';
            case 'roff' : return  'application/x-troff';
            case 'rpm' : return  'audio/x-pn-realaudio-plugin';
            case 'rtf' : return  'text/rtf';
            case 'rtx' : return  'text/richtext';
            case 'scm' : return  'application/x-lotusscreencam';
            case 'set' : return  'application/set';
            case 'sgm' : return  'text/sgml';
            case 'sgml' : return  'text/sgml';
            case 'sh' : return  'application/x-sh';
            case 'shar' : return  'application/x-shar';
            case 'silo' : return  'model/mesh';
            case 'sit' : return  'application/x-stuffit';
            case 'skd' : return  'application/x-koan';
            case 'skm' : return  'application/x-koan';
            case 'skp' : return  'application/x-koan';
            case 'skt' : return  'application/x-koan';
            case 'smi' : return  'application/smil';
            case 'smil' : return  'application/smil';
            case 'snd' : return  'audio/basic';
            case 'sol' : return  'application/solids';
            case 'spl' : return  'application/x-futuresplash';
            case 'src' : return  'application/x-wais-source';
            case 'step' : return  'application/STEP';
            case 'stl' : return  'application/SLA';
            case 'stp' : return  'application/STEP';
            case 'sv4cpio' : return  'application/x-sv4cpio';
            case 'sv4crc' : return  'application/x-sv4crc';
            case 'swf' : return  'application/x-shockwave-flash';
            case 't' : return  'application/x-troff';
            case 'tar' : return  'application/x-tar';
            case 'tcl' : return  'application/x-tcl';
            case 'tex' : return  'application/x-tex';
            case 'texi' : return  'application/x-texinfo';
            case 'texinfo' : return 'application/x-texinfo';
            case 'tif' : return  'image/tiff';
            case 'tiff' : return  'image/tiff';
            case 'tr' : return  'application/x-troff';
            case 'tsi' : return  'audio/TSP-audio';
            case 'tsp' : return  'application/dsptype';
            case 'tsv' : return  'text/tab-separated-values';
            case 'txt' : return  'text/plain';
            case 'unv' : return  'application/i-deas';
            case 'ustar' : return  'application/x-ustar';
            case 'vcd' : return  'application/x-cdlink';
            case 'vda' : return  'application/vda';
            case 'viv' : return  'video/vnd.vivo';
            case 'vivo' : return  'video/vnd.vivo';
            case 'vrml' : return  'model/vrml';
            case 'wav' : return  'audio/x-wav';
            case 'wrl' : return  'model/vrml';
            case 'xbm' : return  'image/x-xbitmap';
            case 'xlc' : return  'application/vnd.ms-excel';
            case 'xll' : return  'application/vnd.ms-excel';
            case 'xlm' : return  'application/vnd.ms-excel';
            case 'xls' : return  'application/vnd.ms-excel';
            case 'xlw' : return  'application/vnd.ms-excel';
            case 'xml' : return  'text/xml';
            case 'xpm' : return  'image/x-xpixmap';
            case 'xwd' : return  'image/x-xwindowdump';
            case 'xyz' : return  'chemical/x-pdb';
            case 'zip' : return  'application/zip';
        };
        return '';
    }