Element.insert_html is not function


I have created the application by following the railcast video

However I am getting this error when I click "add element"

RJS error:

TypeError: Element.insert is not a function

and then

Element.insert("docs", { bottom: "<div class=\"doc\">\n\n Doc: <input .....etc

I have added the <%= javascript_include_tag :defaults %> in layout files also

here is my rjs line <%= render :partial => 'task', :collection => @project.tasks %>

please help me in this regards.


Please verify that all included javascript files get successfully loaded into your html page.


    I inserted required java script files in my html page that is new.html.erb

Plaese verify the file...


<% form_for :project, :url => projects_path do |f| %>

  <p>     Name: <%= f.text_field :name %>   </p>

  <div id="tasks">     <%= render :partial => 'task', :collection => @project.tasks %>   </div>

  <%= link_to_function "Add a Task" do |page|

    page.insert_html:bottom, :tasks, :partial => 'task', :object => Task.new   end %>

  <p><%= submit_tag "Create Project" %></p> <% end %>

#My controller i.e projects

class ProjectsController < ApplicationController

def index @projects = Project.find(:all) end

def new   @project = Project.new @project.tasks.build


def create   @project = Project.new(params[:project])   if @project.save     flash[:notice] = "Successfully created project and tasks."     redirect_to projects_path   else     render :action => 'new'   end end

def edit   @project = Project.find(params[:id]) end

def update   params[:project][:existing_task_attributes] ||= {}

  @project = Project.find(params[:id])   if @project.update_attributes(params[:project])     flash[:notice] = "Successfully updated project and tasks."     redirect_to project_path(@project)   else     render :action => 'edit'   end end