javascript动态特效

				/*				Supersized - Full Screen Background/Slideshow jQuery Plugin				supersized.1.0.js				February 2009				By Sam Dunn				www.buildinternet.com / www.onemightyroar.com				*/				(function($){									//Resize image on ready or resize					$.fn.supersized = function() {											var options = $.extend($.fn.supersized.defaults, $.fn.supersized.options);												if (options.slideshow == 1){							setInterval("theslideshow()", options.slideinterval);						}												$().ready(function() {							$('#supersize').resizenow(); 						});						$(window).bind("resize", function(){				    		$('#supersize').resizenow(); 						});					};										//Adjust image size					$.fn.resizenow = function() {												var options = $.extend($.fn.supersized.defaults, $.fn.supersized.options);											  	return this.each(function() {					  									//Define image ratio & minimum dimensions							var minwidth = options.minsize*(options.startwidth);							var minheight = options.minsize*(options.startheight);							var ratio = options.startheight/options.startwidth;														//Gather browser and current image size							var imagewidth = $(this).width();							var imageheight = $(this).height();							var browserwidth = $(window).width();							var browserheight = $(window).height();														//Check for minimum dimensions							if ((browserheight < minheight) && (browserwidth < minwidth)){								$(this).height(minheight);								$(this).width(minwidth);							}							else{									//When browser is taller									if (browserheight > browserwidth){								    imageheight = browserheight;								    $(this).height(browserheight);								    imagewidth = browserheight/ratio;								    $(this).width(imagewidth);								    								    if (browserwidth > imagewidth){								    	imagewidth = browserwidth;								    	$(this).width(browserwidth);								    	imageheight = browserwidth * ratio;								    	$(this).height(imageheight);								    }																}																//When browser is wider								if (browserwidth >= browserheight){								    imagewidth = browserwidth;								    $(this).width(browserwidth);								    imageheight = browserwidth * ratio;								    $(this).height(imageheight);								    								    if (browserheight > imageheight){								    	imageheight = browserheight;								    	$(this).height(browserheight);								    	imagewidth = browserheight/ratio;								    	$(this).width(imagewidth);								    }								}							}							return false;						});					};										$.fn.supersized.defaults = { 							startwidth: 640,  							startheight: 480,							minsize: .5,							slideshow: 1,							slideinterval: 5000  					};									})(jQuery);								//Slideshow Add-on				function theslideshow() {				    				    var currentslide = $('#supersize .activeslide');				    						    if ( currentslide.length == 0 ) currentslide = $('#supersize :last');										    var nextslide =  currentslide.next().length ? currentslide.next() : $('#supersize :first');										    nextslide.addClass('activeslide');				    currentslide.removeClass('activeslide');								}