在jquery验证时下拉和datepicker触发器

Question

I am using codeigniter where I have autocomplete drop down and datepicker. If values are not selected then I am applying validations using jquery. Validations run properly but when I click on submit button drop down list or date picker gets auto trigger if not selected. I dont understand why this is happening

Date Picker is

    $(function ()
    {
      $('#search_date').datepicker
      ({
          format: "dd-mm-yyyy",
          autoclose: true,
          clearBtn : "true" ,
          startDate: new Date() ,
       })
    });

validations are

$( document ).ready(function() { 


$(":submit").on('click',function(){

$('#search_form').validate({
    rules: {

            loading:
            {
                required:true
            },
            discharge:
            {
                required:true
            },
            search_date:
            {
                required:true                   
            }
    },
    messages: {

            loading:
            {
                required:"Required!"    
            },          

            discharge:
            {
                required:"Required!"
            },
            search_date:
            {
                required:"Required!"                    
            }

    errorElement: "span",
    errorPlacement: function(error, element) {               
                error.appendTo(element.parent());     
            },

   submitHandler: function (form) {

                   if ($(form).valid()) 
                       form.submit(); 
                   return false; // prevent normal form posting

    }
});
});
});