randomParse.rb in javascript

randomParse.js

var query = new Parse.Query("Classname");
query.count({
  error: function(error) {
  	// Error counting objects
  },
  success: function(count) {
    query.skip(Math.floor(Math.random() * (count - 1)));
    query.first({
      error: function(error){
        // Error getting object
      },
      success: function(object) {
        // Your random object
      }
    });
  }
});

Here it in in Coffeescript (untested):

query = new Parse.Query("Classname")
query.count
  error: (error) -> 
    # Error counting objects
  success: (count) ->
    query.skip Math.floor(Math.random() * (count - 1))
    query.first
      error: (error) ->
      # Error getting object
      success: (object) ->
        # Your random object

count and skip can be inefficient. Have you considered doing it this way instead?

https://parse.com/questions/is-it-possible-to-query-for-a-random-object