gistfile1.js

jQuery(document).ready( function() {
   // this will run after page load
   DUDE.rollover.init();
});

// creates DUDE hash/object
DUDE = {};

// Setup DUDE.rollover child object expando
// DUDE.rollover becomes the main object context
DUDE.rollover = {
  /* defins DUDE.rollover.init()
     - the init is called after the page loads!!!
       by then the other functions below have been set into memory
       otherwise this function would depend on functions that hasn't been parsed yet
  */
  init: function() {
    this.preload();
    jQuery(".ro").hover(
      // over
      function () { jQuery(this).attr( 'src', DUDE.rollover.newimage(jQuery(this).attr('src')) ); },
      // out
      function () { jQuery(this).attr( 'src', DUDE.rollover.oldimage(jQuery(this).attr('src')) ); }
    );
  },
  // defines DUDE.rollover.preload() function
  preload: function() {
    jQuery(window).bind('load', function() {
      jQuery('.ro').each( function( key, elm ) { jQuery('<img>').attr( 'src', DUDE.rollover.newimage( jQuery(this).attr('src') ) ); });
    });
  },
  // defines DUDE.rollover.newimage() function
  newimage: function( src ){ return src.substring( 0, src.search(/(\.[a-z]+)/) ) + '_o' + src.match(/(\.[a-z]+)/)[0]; },
  // defines DUDE.rollover.oldimage() function
  oldimage: function( src ){ return src.replace(/_o/, ''); }
};// ends DUDE.rollover