just replace your code:

old code:$("#dateSelect").datepicker({ showOtherMonths: true, selectOtherMonths: true, changeMonth: true, changeYear: true, showButtonPanel: true, dateFormat: 'yy-mm-dd'

});

new code: $("#dateSelect").datepicker({ showOtherMonths: true, selectOtherMonths: true, changeMonth: true, changeYear: true, showButtonPanel: true, dateFormat: 'yy-mm-dd', minDate: 0 });

just replace your code:

old code:

$("#dateSelect").datepicker({
    showOtherMonths: true,
    selectOtherMonths: true,
    changeMonth: true,
    changeYear: true,
    showButtonPanel: true,
    dateFormat: 'yy-mm-dd'
    
});

new code:

$("#dateSelect").datepicker({
    showOtherMonths: true,
    selectOtherMonths: true,
    changeMonth: true,
    changeYear: true,
    showButtonPanel: true,
    dateFormat: 'yy-mm-dd',
    minDate: 0
});