<input type="text" class="Wdate" onclick="WdatePicker({onpicking:function(dp){sayHello(this,dp);}})" readonly="readonly">

function sayHello(obj,dp){
        var date=dp.cal.getNewDateStr();
        var $obj=$(obj);
        var name=$obj.val();
        alert('您好：'+name+'今天是：'+date)
}