一个例子：

$( "#datepicker" ).datepicker({
    showButtonPanel: true,beforeShow: function( input ) {
        setTimeout(function() {
            var buttonPane = $( input )
                .datepicker( "widget" )
                .find( ".ui-datepicker-buttonpane" );
 
            $( "<button>",{
                text: "Clear",click: function() {
                //Code to clear your date field (text Box,read only field etc.) I had to remove the line below and add custom code here
                    $.datepicker._clearDate( input );
                }
            }).appendTo( buttonPane ).addClass("ui-datepicker-clear ui-state-default ui-priority-primary ui-corner-all");
        },1 );
    },onChangeMonthYear: function( year,month,instance ) {
        setTimeout(function() {
            var buttonPane = $( instance )
                .datepicker( "widget" )
                .find( ".ui-datepicker-buttonpane" );
 
            $( "<button>",read only field etc.) I had to remove the line below and add custom code here
                    $.datepicker._clearDate( instance.input );
                }
            }).appendTo( buttonPane ).addClass("ui-datepicker-clear ui-state-default ui-priority-primary ui-corner-all");
        },1 );
    }
});