Web Programming Step by Step

Lecture 20
Scriptaculous

Reading: 12.1 - 12.2

Except where otherwise noted, the contents of this presentation are Copyright 2010 Marty Stepp and Jessica Miller.

Scriptaculous overview

Scriptaculous : a JavaScript library, built on top of Prototype, that adds:

• visual effects (animation, fade in/out, highlighting)
• drag and drop
• Ajax features:
  • Auto-completing text fields (drop-down list of matching choices)
  • In-place editors (clickable text that you can edit and send to server)
• some DOM enhancements
• other stuff (unit testing, etc.)

Downloading and using Scriptaculous

<script src="http://ajax.googleapis.com/ajax/libs/prototype/1.7.0.0/prototype.js"
 type="text/javascript"></script>

<script src="http://ajax.googleapis.com/ajax/libs/scriptaculous/1.8.3/scriptaculous.js"
 type="text/javascript"></script>

• or download it, extract its .js files to your project folder
• documentation available on the Scriptaculous wiki
• Scriptaculous Effects Cheat Sheet

Visual effects (12.2.1)

appear blindDown grow slideDown (appearing)

blindUp dropOut fade fold puff
shrink slideUp squish switchOff (disappearing)

highlight pulsate shake morph
Effect.Move Effect.Scale Effect.toggle (blind) (Getting attention)

Click effects above

Adding effects to an element

element.effectName();   // for most effects

// some effects must be run the following way:
new Effect.name(element or id);

$("sidebar").shake();

var buttons = $$("results > button");
for (var i = 0; i < buttons.length; i++) {
	buttons[i].fade();
}

• the effect will begin to animate on screen (asynchronously) the moment you call it
• six core effects are used to implement all effects on the previous slides:
  • Effect.Highlight, Effect.Morph, Effect.Move,
    Effect.Opacity, Effect.Parallel, Effect.Scale

Effect options

element.effectName(
	{
		option: value,
		option: value,
		...
	}
);

$("my_element").pulsate({
	duration: 2.0, 
	pulses: 2
});

• many effects can be customized by passing additional options (note the {})
• options (wiki): delay, direction, duration, fps, from, queue, sync, to, transition
• Q: How would we show two effects in a row on the same element?

Effect events

$("my_element").fade({
	duration: 3.0, 
	afterFinish: displayMessage
});

function displayMessage(effect) {
	alert(effect.element + " is done fading now!");
}

• all effects have the following events that you can handle:
  • beforeStart, beforeUpdate, afterUpdate, afterFinish
• the afterFinish event fires once the effect is done animating
  • useful do something to the element (style, remove, etc.) when effect is done
• each of these events receives the Effect object as its parameter
  • its properties: element, options, currentFrame, startOn, finishOn
  • some effects (e.g. Shrink) are technically "parallel effects", so to access the modified element, you write effect.effects[0].element rather than just effect.element

Drag and drop (12.2.2)

Scriptaculous provides several objects for supporting drag-and-drop functionality:

• Draggable : an element that can be dragged
• Draggables : manages all Draggable objects on the page
• Droppables : elements on which a Draggable can be dropped
• Sortable : a list of items that can be reordered

• Shopping Cart demo

Draggable

new Draggable(element or id,
	{ options }
);

• specifies an element as being able to be dragged
• options: handle, revert, snap, zindex, constraint, ghosting, starteffect, reverteffect, endeffect
• event options: onStart, onDrag, onEnd
  • each handler function accepts two parameters: the Draggable object, and the mouse event

Draggable example

<div id="draggabledemo1">Draggable demo. Default options.</div>
<div id="draggabledemo2">Draggable demo.
	{snap: [40,40], revert: true}</div>

document.observe("dom:loaded", function() {
	new Draggable("draggabledemo1");
	new Draggable("draggabledemo2", {revert: true, snap: [40, 40]});
});

Draggable demo.
Default options.

Draggable demo.
{snap:[60, 60], revert:true}

Draggables

• a global helper for accessing/managing all Draggable objects on a page
• (not needed for this course)
• properties: drags, observers
• methods: register, unregister, activate, deactivate, updateDrag, endDrag, keyPress, addObserver, removeObserver, notify

Droppables

Droppables.add(element or id,
	{ options }
);

• specifies an element as being able to be dragged
• options: accept, containment, hoverclass, overlap, greedy
• event options: onHover, onDrop
  • each callback accepts three parameters: the Draggable, the Droppable, and the event
  • Shopping Cart demo

Drag/drop shopping demo

<img id="product1" src="images/shirt.png" alt="shirt" />
<img id="product2" src="images/cup.png" alt="cup" />
<div id="droptarget"></div>

document.observe("dom:loaded", function() {
	new Draggable("product1");
	new Draggable("product2");
	Droppables.add("droptarget", {onDrop: productDrop});
});

function productDrop(drag, drop, event) {
	alert("You dropped " + drag.id);
}

Sortable

Sortable.create(element or id of list,
	{ options }
);

• specifies a list (ul, ol) as being able to be dragged into any order
• implemented internally using Draggables and Droppables
• options: tag, only, overlap, constraint, containment, format, handle, hoverclass, ghosting, dropOnEmpty, scroll, scrollSensitivity, scrollSpeed, tree, treeTag
• to make a list un-sortable again, call Sortable.destroy on it

Sortable demo

<ol id="simpsons">
	<li id="simpsons_0">Homer</li>
	<li id="simpsons_1">Marge</li>
	<li id="simpsons_2">Bart</li>
	<li id="simpsons_3">Lisa</li>
	<li id="simpsons_4">Maggie</li>
</ol>

document.observe("dom:loaded", function() {
	Sortable.create("simpsons");
});

Sortable list events

document.observe("dom:loaded", function() {
	Sortable.create("simpsons", {
			onUpdate: listUpdate
	});
});

• onChange handler function receives the dragging element as its parameter
• onUpdate handler function receives the list as its parameter

Sortable list events example

document.observe("dom:loaded", function() {
	Sortable.create("simpsons", {
			onUpdate: listUpdate
	});
});

function listUpdate(list) {
	// can do anything I want here; effects, an Ajax request, etc.
	list.shake();
}

Subtleties of Sortable events

• for onUpdate to work, each li must have an id of the form listID_index

  <ol id="simpsons">
  	<li id="simpsons_0">Homer</li>
  	<li id="simpsons_1">Marge</li>
  	<li id="simpsons_2">Bart</li>
  	<li id="simpsons_3">Lisa</li>
  	<li id="simpsons_4">Maggie</li>
  </ol>
  

• if the elements of the list change after you make it sortable (if you add or remove an item using the DOM, etc.), the new items can't be sorted
  • must call Sortable.create on the list again to fix it

Auto-completing text fields (12.2.3)

Scriptaculous offers ways to make a text box that auto-completes based on prefix strings:

• Autocompleter.Local : auto-completes from an array of choices
• Ajax.Autocompleter : fetches and displays list of choices using Ajax

Using Autocompleter.Local

new Autocompleter.Local(
	element or id of text box, 
	element or id of div to show completions,
	array of choices, 
	{ options }
);

• you must create an (initially empty) div to store the auto-completion matches
  • it will be inserted as a ul that you can style with CSS
  • the user can select items by pressing Up/Down arrows; selected item is given a class of selected
• pass the choices as an array of strings
• pass any extra options as a fourth parameter between { }
  • options: choices, partialSearch, fullSearch, partialChars, ignoreCase

Autocompleter.Local demo

<input id="bands70s" size="40" type="text" />
<div id="bandlistarea"></div>

document.observe("dom:loaded", function() {
	new Autocompleter.Local(
		"bands70s",
		"bandlistarea",
		["ABBA", "AC/DC", "Aerosmith", "America", "Bay City Rollers", ...], 
		{}
	);
});

Autocompleter styling

<input id="bands70s" size="40" type="text" />
<div id="bandlistarea"></div>

#bandlistarea {
	border: 2px solid gray;
}
/* 'selected' class is given to the autocomplete item currently chosen */
#bandlistarea .selected {
	background-color: pink;
}

Using Ajax.Autocompleter

new Ajax.Autocompleter(
	element or id of text box, 
	element or id of div to show completions,
	url, 
	{ options }
);

• when you have too many choices to hold them all in an array, you can instead fetch subsets of choices from the server using Ajax
• instead of passing choices as an array, pass a URL from which to fetch them
  • the choices are sent back from the server as an HTML ul with li elements in it
• options: paramName, tokens, frequency, minChars, indicator, updateElement, afterUpdateElement, callback, parameters

Ajax.InPlaceEditor

new Ajax.InPlaceEditor(element or id,
	url,
	{ options }
);

• options: okButton, okText, cancelLink, cancelText, savingText, clickToEditText, formId, externalControl, rows, onComplete, onFailure, cols, size, highlightcolor, highlightendcolor, formClassName, hoverClassName, loadTextURL, loadingText, callback, submitOnBlur, ajaxOptions
• event options: onEnterHover, onLeaveHover, onEnterEditMode, onLeaveEditMode

Ajax.InPlaceCollectionEditor

new Ajax.InPlaceCollectionEditor(element or id,
	url,
	{
		collection: array of choices,
		options
	}
);

• a variation of Ajax.InPlaceEditor that gives a collection of choices
• requires collection option whose value is an array of strings to choose from
• all other options are the same as Ajax.InPlaceEditor

Playing sounds (API)

Sound.play("music/java_rap.mp3");
Sound.play("music/wazzaaaaaap.wav");

• to silence a sound playing in progress, use Sound.play('', {replace: true});
• cannot play sounds from a local computer (must be uploaded to a web site)

Other neat features

• slider control:

  new Control.Slider("id of knob", "id of track", {options});
  

• Builder - convenience class to replace document.createElement :

  var img = Builder.node("img", {
    src: "images/lolcat.jpg",
    width: 100, height: 100,
    alt: "I can haz Scriptaculous?"
  });
  $("main").appendChild(img);
  

• Tabbed UIs