dropzone upload only one file

maxFiles: 1 is used to tell dropzone that there should be only one file. When there is more than 1 file the function maxfilesexceeded will be called, with the exceeding file as the first parameter.

here is a simple function to delete preview of first file and add the new one 🙂

maxFiles:1,
init: function() {
      this.on("maxfilesexceeded", function(file) {
            this.removeAllFiles();
            this.addFile(file);
      });
}