在制作网站时避免图片太平淡经常会用到动画效果：由小到大跳跃出现。这种效果很有视觉冲击力，显著提高关注度~

原理：利用css3的动画属性@keyframes@-moz-keyframes@-webkit-keyframes定义动画suofang,再用animation调用suofang这一动画帧，并将动画添加到图片上，需要注意的是需要给图片相当于初始化的一个处理

transform:scale(0);
    -moz-transform:scale(0);
    -webkit-transform:scale(0);

最后在js中调用css动画。对于不同的页面，需要使用index来标注不同的页面。

 1 <!--第二屏开始-->
 2     <div class="section">
 3         <div class="mdmobile-second-one">
 4             <div class="mdmobile-second-one-top">
 5                 <img src="images/06_03.png"   class="mdmobile-second-one-top-top"/>
 6                 <img src="images/06_07.png"   class="mdmobile-second-one-top-foot"/>
 7             </div>
 8 
 9             <div class="mdmobile-second-one-middle">
10                 <div class="mdmobile-second-one-middle-top">
11                     <img src="images/07_03.png"  class="mdmobile-second-one-middle-top-left"/>
12                     <img src="images/07_05.png"   class="mdmobile-second-one-middle-top-right"/>
13                     <div class="clear"></div>
14                 </div>
15                 <div class="mdmobile-second-one-middle-middle">
16                     <img src="images/07_09.png"  class="mdmobile-second-one-middle-middle-one"/>
17                     <img src="images/07_11.png"   class="mdmobile-second-one-middle-middle-two"/>
18                     <img src="images/07_13.png"  class="mdmobile-second-one-middle-middle-three"/>
19                     <div class="clear"></div>
20                 </div>
21 　　　　　　　　　　<div class="mdmobile-second-one-middle-foot">
22                     <img src="images/07_16.png"  class="mdmobile-second-one-middle-foot-left"/>
23                     <img src="images/07_18.png"  class="mdmobile-second-one-middle-foot-right"/>
24                     <div class="clear"></div>
25                 </div>
26             </div>
27             <div class="mdmobile-second-one-foot">
28             </div>
29         </div>
30     </div>
31     <!--第二屏结束-->

 1 /*第二屏开始*/
 2 
 3 @keyframes  suofang {
 4     0% {transform:scale(0.2);}
 5     100% {transform:scale(1.0);}
 6 }
 7 @-moz-keyframes  suofang {
 8     0% {-moz-transform:scale(0.2);}
 9     100% {-moz-transform:scale(1.0);}
10 }
11 @-webkit-keyframes  suofang {
12     0% {-webkit-transform:scale(0.2);}
13     100% {-webkit-transform:scale(1.0);}
14 }
15 .mdmobile-second-one-middle-top-right.active,
16 .mdmobile-second-one-middle-top-left.active,
17 .mdmobile-second-one-middle-middle-one.active,
18 .mdmobile-second-one-middle-middle-two.active,
19 .mdmobile-second-one-middle-middle-three.active,
20 .mdmobile-second-one-middle-foot-left.active,
21 .mdmobile-second-one-middle-foot-right.active
22 {
23     animation: suofang 1s forwards;
24     -moz-animation: suofang 1s forwards;
25     -webkit-animation: suofang 1s forwards;
26 }
27 .mdmobile-second-one-middle-top-right,
28 .mdmobile-second-one-middle-top-left,
29 .mdmobile-second-one-middle-middle-one,
30 .mdmobile-second-one-middle-middle-two,
31 .mdmobile-second-one-middle-middle-three,
32 .mdmobile-second-one-middle-foot-left,
33 .mdmobile-second-one-middle-foot-right
34 {
35     transform:scale(0);
36     -moz-transform:scale(0);
37     -webkit-transform:scale(0);
38 }

if(index == 2){
                $(".mdmobile-second-one-middle-top-left").addClass("active");
                setTimeout(function(){
                    $(".mdmobile-second-one-middle-top-right").addClass("active");
                },100);
                setTimeout(function(){
                    $(".mdmobile-second-one-middle-middle-one").addClass("active");
                },200);
                setTimeout(function(){
                    $(".mdmobile-second-one-middle-middle-two").addClass("active");
                },300);
                setTimeout(function(){
                    $(".mdmobile-second-one-middle-middle-three").addClass("active");
                },400);
                setTimeout(function(){
                    $(".mdmobile-second-one-middle-foot-left").addClass("active");
                },500);
                setTimeout(function(){
                    $(".mdmobile-second-one-middle-foot-right").addClass("active");
                },600);
            }