external button to fire dropzone.js
//use the following command:
myDropzone.hiddenFileInput.click()
//to find dropzone instant there are several ways:
//1- by jquery:
var myDropZone = $('.dropzone').get(0).dropzone;
//or
var myDropZone = $("div#dropmehere").dropzone({...}); //if you are using id to find your element
//2- by Dropzone class itself:
var myDropzone = Dropzone.forElement("div#dropmehere");