HTMLのメッセージボタンに数量添字を実装する例の詳細説明

<a  onclick="goMessage();" style="width: 60px;height: 100%;color: white;background: transparent;" href="#" class="easyui-linkbutton" data-options="iconCls:&#39;fa fa-bell-o fa-2x&#39;,size:&#39;large&#39;,iconAlign:&#39;top&#39;">
消息<span id="msgNum" class="ii">4</span>
</a>

/*角标 */
    .ii{
        display: none;
        background: #f00;
        border-radius: 50%;
        width: 20px;
        height: 20px;
        top: 5px;
        right: 0px;
        position: absolute;
        text-align: center;
        color: #FFF;
        z-index: 99999;
    }

function ajaxa(){
         $.ajax({
                type:"POST",
                dataType : "json",
                async: false,
                url : "${pageContext.request.contextPath}/docinf/sendInform/lookForMsgNum.do",
                data : {},
                success : function(data){
                    if(data !=null){
                        if(parseInt(data)>10){
                            $("#msgNum").show();
                            $("#msgNum").text(parseInt(data));
                        }else if(parseInt(data)> 0){
                            $("#msgNum").show();
                            $("#msgNum").text(parseInt(data));
                        }else{
                            $("#msgNum").hide();
                        }
                    }
                },
                error:function(){
                }
            });
    }