On validation prevent calender control to open

I want to prevent open calendar control on save button at time of validation fire , I am not able to find how can I prevent It

I have one calendar control in form , select date validation fire on save button after validation it will direct focus on calendar control and open calendar automatically , business don’t want to open calendar control

HTML

<div class="col-lg-3 col-md-4 col-sm-6">
           <div class="form-group datepicker">
                   <label>Project Start Date </label>
                       <asp:TextBox ID="ProjectStartDate" TabIndex="27" ClientIDMode="Static" runat="server" CssClass="form-control"></asp:TextBox>
                        <asp:HiddenField ID="hdnProjectStartDate" runat="server" Value="" />
            </div>
 </div>

I want to prevent open calendar open on save button
let me know if any solution over there

Thank you

Answer

I have solve this issue to change in formValidation.JS
In this file there is one function

      // Determined the first invalid field which will be focused on automatically
        var ns = this._namespace;
        for (var i = 0; i < this.$invalidFields.length; i++) {
            var $field    = this.$invalidFields.eq(i),
                autoFocus = this.isOptionEnabled($field.attr('data-' + ns + '-field'), 'autoFocus');
            if (autoFocus) {
                // Focus the field 
                //$field.focus();                    
                return false;
                break;
            }
        }

On validation it will auto focus that element & after focus calendar control will open automatically because of focus

Comment this line for prevent focus on calendar control

 $field.focus();    

Thank you !!