css闪动效果 ----样式发生快速的变化

DOCTYPE >
html>
    head>
        title>JS+CSS做文字闪烁title>
        meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        style>
            .wa{
                font-size:13px;  
                color: #0000FF;  
            }
            .wa2{
                font-size:13px;  
                color: #FFFF00; 
            }
            .sty1{
                display: block;    
            }
            .sty2{
                display: none;    
            }
         style>
    head>
    body>
         span class="wa" id="shan">北京青年span>
         div class="sty1" id="pic">
             img src="../img/girl.jpg" />
         div>
         script type="text/javascript">
             function change(){
                 var ss = document.getElementById("shan");
                 if(ss.className == "wa"){
                     ss.className = "wa2";
                 }else{
                     ss.className = "wa";
                 }
                 setTimeout("change()",100);
             }
             change();
             picChange();
             function picChange(){
                 var pic = document.getElementById("pic");
                 if(pic.className == "sty1"){
                     pic.className = "sty2";
                 }else {
                     pic.className = "sty1";
                 }
                 setTimeout("picChange()",50);
             }
         script>
    body>
html>