1//use the following command:
2myDropzone.hiddenFileInput.click()
3
4//to find dropzone instant there are several ways:
5//1- by jquery: 
6var myDropZone =  $('.dropzone').get(0).dropzone;
7//or
8var myDropZone = $("div#dropmehere").dropzone({...});  //if you are using id to find your element
9
10//2- by Dropzone class itself: 
11var myDropzone = Dropzone.forElement("div#dropmehere");