Working with Special Effects Creating Rollovers, Menus, Filters, and Transitions

2 Objectives Understand how to work with the JavaScript document.images collection Create image objects and image object arrays Set the properties of image objects Create image rollovers with image objects and the document.images collection Understand how to create text rollovers Understand how to work with pop-up and pull-down menus Hide and unhide objects in a Web page Understand and implement Internet Explorer’s filter styles Understand and apply Internet Explorer’s transition styles

3 Working with Image Objects

4 Referencing an Inline Image –Each inline image is part of an array of images in the document called the image collection document.images[idref] document.images.idref –Other forms document.getElementBy(“id”) document.name

5 Working with Image Objects Referencing an Inline Image

6 Working with Image Objects Creating an Image object –JavaScript treats all inline images as objects known as image objects –To create a new image object image = new Image(width, height);

7 Working with Image Objects Properties of Image Objects

8 Working with Image Objects Detecting Image Objects –It is possible that your users will be running a very early browser version –Can use object detection to determine each user’s level of browser support

9 Creating an Image Rollover An image rollover is created when you change the source of an inline image from one graphic file to another

10 Creating an Image Rollover Preloading the Images –Performance is an important consideration when creating a rollover effect –Can preload all of the image objects a user may need, storing the images in the browser’s memory –It is often more efficient to store your image objects in arrays

11 Creating an Image Rollover Preloading the Images –Example

12 Creating an Image Rollover Swapping Image Objects –Once the images are preloaded, you can use JavaScript to swap the source for one image with the source for another

13 Creating an Image Rollover Running the Image Rollover

14 Creating a Text Rollover Using the Hover Pseudo-Class a:hover {styles} –Example a:hover {color: red; font-weight:bold} General Text Rollovers –Modify the style properties of an element in response to the rollover event

15 Working with Menus

16 Working with Menus Creating a Pop-Up Menu –In a pop-up menu, a user clicks an object on the page and the menu appears, sometimes elsewhere on the page

17 Working with Menus Creating a Pull-Down Menu –In a pull-down menu, part of the menu is visible –When a user clicks the visible part, the rest of the menu is revealed

18 Creating Pop-Up Menu Functions

19 Creating Pop-Up Menu Functions Displaying Menu Contents

20 Creating Pop-Up Menu Functions Calling the Menu Functions

21 Creating Pop-Up Menu Functions Calling the Menu Functions

22 Working with Internet Explorer Filters A filter is an effect that is applied to an object or page to change its appearance Is applied by adding a filter style to the Web page’s style sheet or by running a JavaScript command that applies a filter to an object

23 Working with Internet Explorer Filters Applying Filters by Using Styles –In version 4.0 filter: filter_name(params) –In versions 5.5 and above filter: progid:DXImageTransorm.Microsoft.filter_name(params)

24 Working with Internet Explorer Filters

25 Working with Internet Explorer Filters Applying Filters by Using Styles

26 Working with Internet Explorer Filters Applying Filters by Using Styles

27 Working with Internet Explorer Filters Running Filters with JavaScript object.style.filter = “filter text”; –Internet Explorer’s version of JavaScript also recognizes the filter collection object.filters[idref] object.filters[“name”] –You can reference specific parameters within each filter using filter.param

28 Working with Internet Explorer Filters Adding a Filter Effect to the Plays Page

29 Working with Internet Explorer Filters Using a Light Filter –In 4.0 filter: Light() –In 5.5 or better Filter: progid:DKImageTransform.Microsoft.Light() –To add ambient light object.filters.Light.addAmbient(red, green, blue, strength)

30 Working with Internet Explorer Filters Using a Light Filter –To add a point light source object.filters.Light.addPoint(x, y, z, red, green, blue, strength) –To add a light source that shines at an angle object.filters.Light.addCone(x, y, z, x2, y2, red, green, blue, strength, spread) –To move the light source to another location object.filters.Light.moveLight(light, x, y, z, absolute)

31 Working with Internet Explorer Filters Using a Light Filter –To change the color of the light object.filters.Light.changeColor(light, red, green, blue, absolute) –To change the intensity of the light source object.filters.Light.changeStrength(light, strength, absolute) –To remove all of the light sources object.filters.Light.clear()

32 Working with Transitions A transition is a visual effect that is applied to an object over an interval of time Applying Transition Styles –A blend transition is a transition in which one object is blended into another filter: blendTrans(duration = value) –A reveal transition is a more general transition in which a visual effect is applied as one object is changed into another filter: revealTrans(duration = value)

33 Working with Transitions Applying Transition Styles

34 Working with Transitions

35 Working with Transitions Applying Transition Styles

36 Working with Transitions Scripting Transitions –Code for scripting a transition follows the same syntax used for filters

37 Working with Transitions Running a Transition –Involves four steps Setting the initial state of the object Applying a transition to the object Specifying the final state of the object Playing the transition

38 Working with Transitions Adding a Transition to the Plays Page

39 Working with Transitions Adding a Transition to the Plays Page

40 Working with Transitions Using Interpage Transitions –Interpage transitions involve effects applied to a page when a browser either enters or exits the page

41 Tips for working with Special Effects Preload all images used in image rollovers to speed up the rollover effect Place rollover images in image arrays to make it easier to write programs that swap the images Place long lists of links into pop-up or pull- down menus to save screen space

42 Tips for working with Special Effects Place filter styles in separate style declarations to avoid problems with older browsers If you use filter or transition styles, test your Web site on non-Internet Explorer browsers to ensure that their use does not cause problems for those browsers