javascript 雪花飘落 js雪花特效代码

  

<script type="text/javascript"> 

     (function($){ 

         $.fn.snow = function(options){ 

             var $flake = $('<div id="snowbox" />').css({'position': 'absolute','z-index':'9999', 'top': '-50px'}).html('❄'), 

             documentHeight  = $(document).height(), 

             documentWidth   = $(document).width(), 

             defaults = { 

                 minSize     : 10, 

                 maxSize     : 20, 

                 newOn       : 1000, 

                 flakeColor  : "#AFDAEF" /* 此处可以定义雪花颜色，若要白色可以改为#FFFFFF */ 

             }, 

             options = $.extend({}, defaults, options); 

             var interval= setInterval( function(){ 

                 var startPositionLeft = Math.random() * documentWidth - 100, 

                 startOpacity = 0.5 + Math.random(), 

                 sizeFlake = options.minSize + Math.random() * options.maxSize, 

                 endPositionTop = documentHeight - 200, 

                 endPositionLeft = startPositionLeft - 500 + Math.random() * 500, 

                 durationFall = documentHeight * 10 + Math.random() * 5000; 

                 $flake.clone().appendTo('body').css({ 

                     left: startPositionLeft, 

                     opacity: startOpacity, 

                     'font-size': sizeFlake, 

                     color: options.flakeColor 

                 }).animate({ 

                     top: endPositionTop, 

                     left: endPositionLeft, 

                     opacity: 0.2 

                 },durationFall,'linear',function(){ 

                     $(this).remove() 

                 }); 

             }, options.newOn); 

         }; 

     })(jQuery); 

     $(function(){ 

     $.fn.snow({ 

     minSize: 5, /* 定义雪花最小尺寸 */ 

     maxSize: 50,/* 定义雪花最大尺寸 */ 

     newOn: 300  /* 定义密集程度，数字越小越密集 */ 

     }); 

     }); 
    </script>

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