HTML：

 < div id =datepicker>< / div> 
  $ p> 

  jQuery ：
  $（'＃datepicker'）。datepicker（{
 beforeShowDay：function（date）{
 if（date == myDate）{
 return [true，'css-class'，'ToolTip']; 

} 
} 
}）; 
 
您需要为 css-class 。有关详情，请点击此处 
 
I have a jQuery UI calendar widget that's displayed in my web application. I'd like to be able to highlight a specific day of the month when the user performs an action. Is there any way to do this?
HTML :
<div id="datepicker"></div>
jQuery : 
$('#datepicker').datepicker({
            beforeShowDay: function(date) {
             if (date == myDate) {
              return [true, 'css-class', 'ToolTip'];

              }
           }
});
You need to write a CSS class for css-class. For more information Click Here