Update Widget Events.ipynb

Running Widget Events.ipynb in http://try.jupyter.org/ raises the following errors:

In [11]: AttributeError: 'module' object has no attribute 'link'
In [12]: AttributeError: 'module' object has no attribute 'dlink'

In [13]: widgets.<Tab> shows 'jsdlink' and 'jslink', which generate the expected linked sliders.

examples/Interactive Widgets/Widget Events.ipynb

@@ -1,383 +1,383 b''
 {
  "cells": [
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "[Index](Index.ipynb) - [Back](Widget List.ipynb) - [Next](Widget Styling.ipynb)"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
    "source": [
     "# Widget Events"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "## Special events"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "from __future__ import print_function"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "The `Button` is not used to represent a data type.  Instead the button widget is used to **handle mouse clicks**.  The **`on_click` method** of the `Button` can be used to register function to be called when the button is clicked.  The doc string of the `on_click` can be seen below."
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "from IPython.html import widgets\n",
     "print(widgets.Button.on_click.__doc__)"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
    "source": [
     "### Example"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "Since button clicks are **stateless**, they are **transmitted from the front-end to the back-end using custom messages**.  By using the `on_click` method, a button that prints a message when it has been clicked is shown below."
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "from IPython.display import display\n",
     "button = widgets.Button(description=\"Click Me!\")\n",
     "display(button)\n",
     "\n",
     "def on_button_clicked(b):\n",
     "    print(\"Button clicked.\")\n",
     "\n",
     "button.on_click(on_button_clicked)"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
    "source": [
     "### on_sumbit"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "The **`Text`** also has a special **`on_submit` event**.  The `on_submit` event **fires when the user hits return**."
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "text = widgets.Text()\n",
     "display(text)\n",
     "\n",
     "def handle_submit(sender):\n",
     "    print(text.value)\n",
     "\n",
     "text.on_submit(handle_submit)"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
    "source": [
     "## Traitlet events"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "**Widget properties are IPython traitlets** and **traitlets are eventful**.  To handle  changes, the **`on_trait_change` method** of the widget can be used to **register a callback**.  The doc string for `on_trait_change` can be seen below."
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "print(widgets.Widget.on_trait_change.__doc__)"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
    "source": [
     "### Signatures"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "Mentioned in the doc string, the callback registered can have **4 possible signatures**:\n",
     "\n",
     "- callback()\n",
     "- callback(trait_name)\n",
     "- callback(trait_name, new_value)\n",
     "- callback(trait_name, old_value, new_value)\n",
     "\n",
     "Using this method, an example of how to output an `IntSlider`'s value as it is changed can be seen below."
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "int_range = widgets.IntSlider()\n",
     "display(int_range)\n",
     "\n",
     "def on_value_change(name, value):\n",
     "    print(value)\n",
     "\n",
     "int_range.on_trait_change(on_value_change, 'value')"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "# Linking Widgets"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "Often, you may want to simply link widget attributes together. Synchronization of attributes can be done in a simpler way than by using bare traitlets events. \n",
     "\n",
     "The first method is to use the `link` and `directional_link` functions from the `traitlets` module. "
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "## Linking traitlets attributes from the server side"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "from IPython.utils import traitlets"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "caption = widgets.Latex(value = 'The values of slider1, slider2 and slider3 are synchronized')\n",
     "sliders1, slider2, slider3 = widgets.IntSlider(description='Slider 1'),\\\n",
     "                             widgets.IntSlider(description='Slider 2'),\\\n",
     "                             widgets.IntSlider(description='Slider 3')\n",
     "l = traitlets.link((sliders1, 'value'), (slider2, 'value'), (slider3, 'value'))\n",
     "display(caption, sliders1, slider2, slider3)"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "caption = widgets.Latex(value = 'Changes in source values are reflected in target1 and target2')\n",
     "source, target1, target2 = widgets.IntSlider(description='Source'),\\\n",
     "                           widgets.IntSlider(description='Target 1'),\\\n",
     "                           widgets.IntSlider(description='Target 2')\n",
     "traitlets.dlink((source, 'value'), (target1, 'value'), (target2, 'value'))\n",
     "display(caption, source, target1, target2)"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "Function `traitlets.link` returns a `Link` object. The link can be broken by calling the `unlink` method."
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "# l.unlink()"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "## Linking widgets attributes from the client side"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "When synchronizing traitlets attributes, you may experience a lag because of the latency dues to the rountrip to the server side. You can also directly link widgets attributes, either in a unidirectional or a bidirectional fashion using the link widgets. "
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "caption = widgets.Latex(value = 'The values of range1, range2 and range3 are synchronized')\n",
     "range1, range2, range3 = widgets.IntSlider(description='Range 1'),\\\n",
     "                         widgets.IntSlider(description='Range 2'),\\\n",
     "                         widgets.IntSlider(description='Range 3')\n",
-    "l = widgets.link((range1, 'value'), (range2, 'value'), (range3, 'value'))\n",
+    "l = widgets.jslink((range1, 'value'), (range2, 'value'), (range3, 'value'))\n",
     "display(caption, range1, range2, range3)"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "caption = widgets.Latex(value = 'Changes in source_range values are reflected in target_range1 and target_range2')\n",
     "source_range, target_range1, target_range2 = widgets.IntSlider(description='Source range'),\\\n",
     "                                             widgets.IntSlider(description='Target range 1'),\\\n",
     "                                             widgets.IntSlider(description='Target range 2')\n",
-    "widgets.dlink((source_range, 'value'), (target_range1, 'value'), (target_range2, 'value'))\n",
+    "widgets.jsdlink((source_range, 'value'), (target_range1, 'value'), (target_range2, 'value'))\n",
     "display(caption, source_range, target_range1, target_range2)"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "Function `widgets.link` returns a `Link` widget. The link can be broken by calling the `unlink` method."
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
     "collapsed": false
    },
    "outputs": [],
    "source": [
     "# l.unlink()"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
     "[Index](Index.ipynb) - [Back](Widget List.ipynb) - [Next](Widget Styling.ipynb)"
    ]
   }
  ],
  "metadata": {
   "cell_tags": [
    [
     "<None>",
     null
    ]
   ],
   "kernelspec": {
    "display_name": "Python 3",
    "language": "python",
    "name": "python3"
   },
   "language_info": {
    "codemirror_mode": {
     "name": "ipython",
     "version": 3
    },
    "file_extension": ".py",
    "mimetype": "text/x-python",
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    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
    "version": "3.4.2"
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