PhantomJS onFilePicker()

page.onFilePicker = function(oldFile) { }

var wpage = require('webpage').create(); 
wpage.onFilePicker = function(oldFile) { 
   console.log('Entering file picker callback'); 
   console.log(oldFile); 
} 
wpage.open("http://localhost/tasks/file.html", function(status) { 
   console.log(status); 

   wpage.evaluate(function() { 
      var fileUp = document.querySelector("#fileToUpload"); 
      var ev = document.createEvent("MouseEvents"); 
      ev.initEvent("click", true, true); 
      fileUp.dispatchEvent(ev); 
   });  
});

Success 
Entering file picker callback