Simple JQuery Image Slide Show with Semi-Transparent Caption

Introduction

Image Slide Show is one of the famous components in web design and development. A lot of the websites display news headlines in an image slide show to attract viewers attention, of course, with caption/excerpt. No doubt about it, this is a clever method not only to gain attentions, but it also makes the website more alive (not too static, dull).

So, here we go again, I separated my codes into 3 sections: html, css and javascript and I will explain how it works in each section.

1. HTML

My ultimate objective is – to keep the html as simple as possible. So, the final product is as following. The first image has a class called “show”. Class show has higher z-index, so image with this class will display on top, thus image with this class will always display on top of the rest. The second thing you need to know is the DIV with “caption” class. It has the highest z-index. That DIV will be used to display the caption. The caption is retrieve from the REL attribute in the img element. You can put html element in the REL attribute. Be aware of extra padding and margin of the html elements you used. (eg h1, p).

Have a look at the html code:

<div id="gallery">
<a href="#" class="show">
<img src="images/flowing-rock.jpg" alt="Flowing Rock" alt="" title="" width="580" height="360" rel="<h3>Flowing Rock</h3>You can put html element
  inside the REL attribute."/></a>
</a>
<a href="#">
<img src="images/grass-blades.jpg" alt="Grass Blades" alt="" title="" width="580" height="360" rel="<h3>Grass Blades</h3>description"/>
</a>

  ......
  ......
  ......
<div class="caption"><div class="content"></div></div>
</div>
<div class="clear"></div>

2. CSS

In this section, I declared a container #gallery for this image slide show. The CSS for this tutorial is pretty straight foward, the most importance thing is the z-index. You have to make sure the “show” class z-index is lower than the “caption” z-index.

body{	font-family:arial}

.clear {
  clear:both
  }

#gallery {
  position:relative;
  height:360px
  }
  #gallery a {
  float:left;
  position:absolute;
  }

  #gallery a img {
  border:none;
  }

  #gallery a.show {
  z-index:500
  }

#gallery .caption {
  z-index:600;
  background-color:#000;
  color:#ffffff;
  height:100px;
  width:100%;
  position:absolute;
  bottom:0;
  }

 #gallery .caption .content {
  margin:5px
  }

  #gallery .caption .content h3 {
  margin:0;
  padding:0;
  color:#1DCCEF;
  }

3. Javascript

Finally, the Javascript code. I have added comments in each line to explain what it does. My concept for this image slide show:

• Hide all the images
• Display the first image and caption
• Find the image with “show” class, and grab the next image using next() method
• Add “show” class to next image
• Animate the image (fadeout the current image, fadein next image)
• And, it repeats above steps over and over again

$(document).ready(function() {		

	//Execute the slideShow	slideShow();

});

function slideShow() {

 //Set the opacity of all images to 0
  $('#gallery a').css({opacity: 0.0});

  //Get the first image and display it (set it to full opacity)
  $('#gallery a:first').css({opacity: 1.0});

  //Set the caption background to semi-transparent
  $('#gallery .caption').css({opacity: 0.7});

 //Resize the width of the caption according to the image width
  $('#gallery .caption').css({width: $('#gallery a').find('img').css('width')});

  //Get the caption of the first image from REL attribute and display it
  $('#gallery .content').html($('#gallery a:first').find('img').attr('rel'))
  .animate({opacity: 0.7}, 400);

  //Call the gallery function to run the slideshow, 6000 = change to next image after 6 seconds
  setInterval('gallery()',6000);

  }

function gallery() {

  //if no IMGs have the show class, grab the first image
  var current = ($('#gallery a.show')? $('#gallery a.show') : $('#gallery a:first'));

 //Get next image, if it reached the end of the slideshow, rotate it back to the first image
  var next = ((current.next().length) ? ((current.next().hasClass('caption'))? $('#gallery a:first') :current.next()) : $('#gallery a:first')); 

  //Get next image caption
  var caption = next.find('img').attr('rel'); 

  //Set the fade in effect for the next image, show class has higher z-index
  next.css({opacity: 0.0})
  .addClass('show')
  .animate({opacity: 1.0}, 1000);

 //Hide the current image
  current.animate({opacity: 0.0}, 1000)
  .removeClass('show');

  //Set the opacity to 0 and height to 1px
  $('#gallery .caption').animate({opacity: 0.0}, { queue:false, duration:0 }).animate({height: '1px'}, { queue:true, duration:300 }); 

  //Animate the caption, opacity to 0.7 and heigth to 100px, a slide up effect
  $('#gallery .caption').animate({opacity: 0.7},100 ).animate({height: '100px'},500 );

  //Display the content
  $('#gallery .content').html(caption);

  }

View Demo | Download Zip

Original Post By: Queness

See Also Following Topics:

• Create a Slideshow Using jQuery
• 7 jQuery Tabbed Interface / Tabbed Structure Menu Tutorial
• jQuery Tips and Tricks
• jQuery Cheatsheet