If you read the source jQuery UI, you can guess:
(function( $, undefined ) { $.effects.effect.explode = function( o, done ) { var rows = o.pieces ? Math.round( Math.sqrt( o.pieces ) ) : 3, cells = rows, el = $( this ), mode = $.effects.setMode( el, o.mode || "hide" ), show = mode === "show", // show and then visibility:hidden the element before calculating offset offset = el.show().css( "visibility", "hidden" ).offset(), // width and height of a piece width = Math.ceil( el.outerWidth() / cells ), height = Math.ceil( el.outerHeight() / rows ), pieces = [], // loop i, j, left, top, mx, my; // children animate complete: function childComplete() { pieces.push( this ); if ( pieces.length === rows * cells ) { animComplete(); } } // clone the element for each row and cell. for( i = 0; i < rows ; i++ ) { // ===> top = offset.top + i * height; my = i - ( rows - 1 ) / 2 ; for( j = 0; j < cells ; j++ ) { // ||| left = offset.left + j * width; mx = j - ( cells - 1 ) / 2 ; // Create a clone of the now hidden main element that will be absolute positioned // within a wrapper div off the -left and -top equal to size of our pieces el .clone() .appendTo( "body" ) .wrap( "<div></div>" ) .css({ position: "absolute", visibility: "visible", left: -j * width, top: -i * height }) // select the wrapper - make it overflow: hidden and absolute positioned based on // where the original was located +left and +top equal to the size of pieces .parent() .addClass( "ui-effects-explode" ) .css({ position: "absolute", overflow: "hidden", width: width, height: height, left: left + ( show ? mx * width : 0 ), top: top + ( show ? my * height : 0 ), opacity: show ? 0 : 1 }).animate({ left: left + ( show ? 0 : mx * width ), top: top + ( show ? 0 : my * height ), opacity: show ? 1 : 0 }, o.duration || 500, o.easing, childComplete ); } } function animComplete() { el.css({ visibility: "visible" }); $( pieces ).remove(); if ( !show ) { el.hide(); } done(); } }; })(jQuery);
Namely, we divide the necessary element into the required number of pieces (9 by default), each of which is a copy of the current one (clones), but with fixed values of length and width, with overflow: hidden. We position the pieces absolutely and set the necessary indents, which are then animated according to a certain law. The original element is initially hidden, and at the end of the animation it becomes visible again. In fact, the code is well documented and, after reading the comments, you can easily figure it out.
