Laravel 5.2 - ajax check if value exists in database

I am creating an employee hierarchy and while setting up the superior for new employee I would like to check if the employee already exists in database ... but :) I would like to do it with AJAX to know it realtime without sending the form ..

I have absolutely no idea how to do it, since I am a newbie to Laravel ..

                           ***UPDATED BASED ON ADVICES:***

I have a form in add_emp.blade.php:

<form action="../create_employee" method="POST">     
    <button class="button" type="submit" style="float:right"><span>Save</span></button>
    <div style="clear:both"></div>
    <fieldset>
      <legend>Personal data</legend>
        <label for="first_name">First name:</label><input type="text" class="add_emp required" name="first_name" value="" /><br />  
        <label for="last_name">Last name:</label><input type="text" class="add_emp required" name="last_name" value="" /><br />
        <label for="superior">Superior:</label><input type="text" class="add_emp" name="superior" value="" id="superior_list" /><br /> 
    </fieldset> 
</form>

Here is a script in add_employee.blade.php

<script type="text/javascript">
    $('#superior_list').blur(function(){

      var first_name = $('#superior_list');

      $.ajax({
        method: "POST",
        url: '/check_superior',
        data: { superior: superior }
      })
      .done(function( msg ) {
        if(msg == 'exist') {
           //employee exists, do something...
           alert( "good." );
        } else {
          //employee does not exist, do something... 
           alert( "bad." );
       }
      });
    })
</script>

route for handling the superior:

Route::post('check_superior', 'EmployeeController@check_superior'); 

This is the Controller function check_superior:

public function check_superior(Request\AjaxUserExistsRequest $request){ 

        if(Employee::where('superior','=',$request->input('superior'))->exists()){
           return "exist";
        }else{                                                                    
           return "not exist";
        }
}

But still not working ... can you advice where could be the issue?

                             *** FINAL SOLUTION ***

Form:

<form action="../create_employee" method="POST">     
    <button class="button" type="submit" style="float:right"><span>Save</span></button>
    <div style="clear:both"></div>
    <fieldset>
      <legend>Personal data</legend>
        <label for="first_name">First name:</label><input type="text" class="add_emp required" name="first_name" value="" /><br />  
        <label for="last_name">Last name:</label><input type="text" class="add_emp required" name="last_name" value="" /><br />
        <label for="superior">Superior:</label><input type="text" class="add_emp" name="superior" value="" id="superior_list" /><span id="check-superior-status"></span><br />
    </fieldset> 
</form>

Add to app.blade.php

meta name="csrf-token" content="{{ csrf_token() }}"

Controller

public function check_superior(Request $request){ 

            if(Employee::where('first_name','=',$request->input('superior_fname'))
                        ->where('last_name','=',$request->input('superior_lname'))
                        ->exists()){
               return "exist";
            }else{                                                                    
               return "not exist";
            }
    }

final emp.blade.php AJAX script

// place data after SEPERIOR selection
        $( "#superior_list" ).blur(function() {

                  var sup_list = $(this).val();
                  var sup_arr = sup_list.split(' ');
                  var superior_fname = sup_arr[0];  
                  var superior_lname = sup_arr[1];
                  var superior = superior_fname+" "+superior_lname;

                  // control print out
                  //$('#check-superior-status').text(superior);

                  // get real data 
                  $.ajax({  
                    headers: {
                        'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
                    },
                    method: "POST",
                    url: '/check_superior',
                    data: { superior_fname: superior_fname, superior_lname: superior_lname },
                    /* // debug only 
                    error: function(xhr, status, error){
                        $('#check-superior-status').text(xhr.responseText);
                    },
                    */
                    success: function(data){
                        $('#check-superior-status').text(data);
                    } 
                  })

        });

This works like a charm :) thank you guys .. hope this will help someone ..