JQuery-选择器

一、层次选择器 

<script type="text/javascript">
        $(function(){
         //祖先 后代(可以跨代)
        //$("div span").attr("class","txt");
        //$("div").find("span").attr("class","txt");
       
        //父辈>子辈(不能跨代)
        //$("div>span").attr("class","txt");
        //$("div").children("span").attr("class","txt");
       
        //元素+相邻元素(大兄弟:单个相邻同级元素)
        //$("div+span").attr("class","txt");
        //$("div").next("span").attr("class","txt");

        //元素~兄弟元素(所有兄弟:所有指定的同级元素)
        //$("div~span").attr("class","txt");//
        //$("div").nextAll("span").attr("class","txt");
      })
      </script>

    二、ID选择器
      <script type="text/javascript">
        $(function(){
            //$(showMsg).attr("class","txt");
            //$("#showMsg").attr("class","txt");
           })
      </script>

  三、元素和样式选择器
    <script type="text/javascript">
        $(function(){       
            $(".divClass").attr("class","txt");//divClass:class名称
            $("div").attr("class","txt");//div:元素名称
 
            $("div,p").attr("class","txt");//div,p:元素名称

</script>