Backstretch

Backstretch is a jQuery plugin that allows you to add a dynamically-resized background image to any page. The image will stretch to fit the page, and will automatically resize as the window size changes.

Providing a full screen background image used to be tricky before the arrival of CSS3 supporting a the following option.

html { 
  background: url(images/bg.jpg) no-repeat center center fixed; 
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

Chris Coyier’s post on Perfect Full Page Backgrounds is a great read.

Options

centeredX

The ratio of the width/height of the image doesn’t always jive with the width/height of the window. This parameter controls whether or not we center the image on the X axis to account for the discrepancy. (type=Boolean, default=true)

centeredY

This parameter controls whether or not we center the image on the Y axis to account for the aforementioned discrepancy. (type=Boolean, default=true)

speed

This is the speed at which the image will fade in, after downloading is complete. Integers are accepted, as well as standard jQuery speed strings (slow, normal, fast). (type=Integer, default=0)

Setup

Include the jQuery library and Backstretch plugin files in your webpage (preferably at the bottom of the page, before the closing BODY tag):

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js"> </script>

<script type="text/javascript" src="/jquery.backstretch.min.js"></script>;

Note: The example above uses the Google hosted version of jQuery; there is also a jQuery source file included with this distribution, if you would like to host it yourself.

<script type="text/javascript">
  $.backstretch("/path/to/image.jpg", {speed: 150});
</script>

Want to change the image after Backstretch has been loaded? No problem, just call it again!

<script type="text/javascript">
  $.backstretch("/path/to/image.jpg", {speed: 150});
  
  // Perhaps you'd like to change the image on a button click
  $(".button").click(function() {
      $.backstretch("/path/to/next_image.jpg");
  });
</script>