Imgur + Phonegap image uploader

phonegap_imgur_uploader.js

// Author: creativepsyco
// More info here; http://api.imgur.com/resources_anon
// Allows only 50 uploads per client.
// GLOBAL VARS
var API_KEY = "YOUR_API_KEY"; // Developer key for imgur
var pictureSource = null;
var destinationType = null;
// Only png and jpg files are supported
// image data should be in base64 encoded stream
//
// The format of the callback_func is 
// function callback_func(img_url, error_string)
//
// If it failed to upload then img_url will be null 
// And error_string will be set to the error type
// Otherwise img_url will contain the url of the uploaded image
// SUPPORTED ERRORS:-
// wrong file format
//
var WRONG_FILE_FORMAT_ERROR = "file format is wrong please check, only png or jpg supported";

var Upload = {
   // The callback function that will be invoked with either link or error
   callback_func: null,
   // file is from a <input> tag or from Drag'n Drop
   upload: function(file, callback_func) {
      
      // Set up the callback first
      Upload.callback_func = callback_func;
      // Checking if the file selected 
      if (!file || file.length<1) {
          Upload.callback_func(null, WRONG_FILE_FORMAT_ERROR);
      }
      
      // It is!
      // Let's build a FormData object
      var fd = new FormData();
      fd.append("image", file); // Append the file
      fd.append("key", API_KEY);
      // Create the XHR (Cross-Domain XHR FTW!!!)
      var xhr = new XMLHttpRequest();
      xhr.open("POST", "http://api.imgur.com/2/upload.json"); // Boooom!
      
      xhr.onload = function() {
         // Big win!
         // The URL of the image is:
         var img_url = JSON.parse(xhr.responseText).upload.links.original;
         console.log("Image url of the uploaded image" + img_url);
         // other flavors of the image
         /***
            "original": "http:\/\/imgur.com\/cSNjk.jpg",
            "imgur_page": "http:\/\/imgur.com\/cSNjk",
            "delete_page": "http:\/\/imgur.com\/delete\/ZnKGru1reZKoabU",
            "small_square": "http:\/\/imgur.com\/cSNjks.jpg",
            "large_thumbnail": "http:\/\/imgur.com\/cSNjkl.jpg"
         */
         // finally callback 
         console.log("Uploaded image url " + img_url);
         if (Upload.callback_func) {
            Upload.callback_func(img_url, "");
         }
      }

      // And now, we send the formdata
      xhr.send(fd);
   },

   // Image Retreival Functions 
   // Gets the photo from the Library
   // callback_function set up :-
   // function callback_func(img_url, message)
   //
   getPhotoFromLibrary: function(callback_func) {
      Upload.callback_func = callback_func;
      // Set up the necessary sources
      pictureSource = navigator.camera.PictureSourceType;
      destinationType = navigator.camera.DestinationType;

      navigator.camera.getPicture(Upload.onPhotoDataSuccess, Upload.onFail, {
         quality: 50,
         destinationType: destinationType.DATA_URL,
         sourceType: pictureSource.PHOTOLIBRARY
      });
   },

   onFail: function(message) {
      if(Upload.callback_func) {
         Upload.callback_func("", message);
      }
   },

   onPhotoDataSuccess: function(imageData) {
      if(Upload.callback_func) {
         Upload.callback_func(imageData, "Success");
      }
   }
}

Hello, how can i put it in a button?