laravel ajax response return html elements

I have used made use of ajax before, but have not encounted this sort of problem,

here is my form

<form action="" method="post" enctype="multipart/form-data" class="m-form m-form--fit m-form--label-align-right" id="basicinfoform">
                                                {{ csrf_field() }}
                                                <input type="hidden" value="{{ $studentinfo->id }}" name="studentformid">
                                                <div class="form-group m-form__group row">
                                                            <center><label for="sphoto">
                                                                        <?php 
                                                                            $photo = "student.png";
                                                                            if($studentinfo->photo !== ""){
                                                                                $photo = $studentinfo->id.'.'.$studentinfo->photo;
                                                                            }
                                                                        ?>
                                                            <img style="width:180px;height:180px;cursor:pointer;border:2px solid lightblue" id="schoollogo" src="<?php echo asset('images/passports/'.$photo) ?>"  alt="">
                                                        </label>
                                                        <input onchange="getPhoto.call(this);showsavebuttonforviewstudentedit();" type="file" class="form-control m-input newb" style="display:none" value="" id="sphoto" name="sphoto" aria-describedby="emailHelp" >
                                                        <br>
                                                            <span class="m-form__help text-accent">
                                                                <b>Click the image to change it</b>
                                                            </span>
                                                        </center>
                                                        <input type="hidden" value="" id="studentid" name="studentid">

                                                </div>

                                                <div class="form-group m-form__group row">
                                                    <div class="col-md-4">
                                                    <label for="exampleInputPassword1">
                                                        Admission No:
                                                    </label>
                                                    <input type="text" disabled="disabled" class="form-control m-input m-input--square"  value="{{ $studentinfo->admissionid }}">
                                                    </div>
                                                    <div class="col-md-4">
                                                    <label for="exampleInputEmail1">
                                                        Full name
                                                    </label>
                                                    <input type="text" name="fullname" class="form-control m-input m-input--square newb" value="{{ $studentinfo->fullname }}" onchange="showsavebuttonforviewstudentedit()">

                                                    </div>

                                                    <div class="col-md-4">
                                                    <label for="exampleInputPassword1">
                                                        Gender
                                                    </label>
                                                    <!-- <input type="password" class="form-control m-input m-input--square" id="exampleInputPassword1" placeholder="Password"> -->
                                                        <select name="gender" id="gender" class="form-control m-input m-input--square newb" onchange="showsavebuttonforviewstudentedit()">
                                                            <option value="1" {{($studentinfo->gender == "1") ? "selected" : ""}}>Male</option>
                                                            <option value="2" {{($studentinfo->gender == "2") ? "selected" : ""}}>Female</option>
                                                        </select>
                                                    </div>                                                        
                                                </div>

                                                <div class="form-group m-form__group row">
                                                    <div class="col-md-4">
                                                    <label for="exampleInputEmail1">
                                                        Class
                                                    </label>
                                                    <!-- <input type="text" class="form-control m-input m-input--square" id="exampleInputEmail1" aria-describedby="emailHelp" placeholder="Enter email"> -->
                                                    <select name="class" id="theclass" class="form-control m-input m-input--square newb" onchange="showsavebuttonforviewstudentedit();getArms();">
                                                        @foreach($allclasses as $list)
                                                            <option value="{{$list->id}}" {{ ($studentinfo->class == $list->id) ? "selected" : ""}}>{{ $list->classname }}</option>
                                                        @endforeach
                                                    </select>
                                                    </div>

                                                    <div class="col-md-4">
                                                    <label for="exampleInputPassword1">
                                                        Arm
                                                    </label>
                                                    <select name="arm" id="thearm" class="form-control m-input m-input--square newb" onchange="showsavebuttonforviewstudentedit()">
                                                        @foreach($allarms as $list)
                                                            <option value="{{$list->id}}" {{ ($studentinfo->arm_id == $list->id) ? "selected" : ""}}>{{ $list->arm }}</option>
                                                        @endforeach
                                                    </select>
                                                    </div>

                                                    <div class="col-md-4">
                                                    <label for="exampleInputPassword1">
                                                        House:
                                                    </label>
                                                    <select name="house" id="house" class="form-control m-input m-input--square newb" onchange="showsavebuttonforviewstudentedit()">
                                                        @foreach($allhouses as $list)
                                                            <option value="{{$list->id}}" {{ ($studentinfo->house == $list->id) ? "selected" : ""}}>{{ $list->house }}</option>
                                                        @endforeach
                                                    </select>
                                                    </div>
                                                </div>

                                                <div class="form-group m-form__group row">
                                                    <div class="col-md-4">
                                                    <label for="exampleInputEmail1">
                                                        Date of Birth
                                                    </label>
                                                    <input type="text" class="form-control m-input m-input--square newb" name=""dob id="dob10" value="{{ $studentinfo->dob}}" onchange="showsavebuttonforviewstudentedit()">
                                                    </div>

                                                    <div class="col-md-4">
                                                    <label for="exampleInputPassword1">
                                                        State
                                                    </label>
                                                    <select name="state" id="stateid" class="form-control m-input m-input--square newb" onchange="getLGA();showsavebuttonforviewstudentedit()">
                                                        @foreach($allstates as $list)
                                                            <option value="{{$list->StateID}}" {{ ($studentinfo->s_of_o == $list->StateID) ? "selected" : ""}}>{{ $list->State }}</option>
                                                        @endforeach
                                                    </select>
                                                    </div>

                                                    <div class="col-md-4">
                                                    <label for="exampleInputPassword1">
                                                        Local Govt.
                                                    </label>
                                                    <select name="lga" id="lgafield" class="form-control m-input m-input--square newb" onchange="showsavebuttonforviewstudentedit()">
                                                        @foreach($alllga as $list)
                                                            <option value="{{$list->lgaId}}" {{ ($studentinfo->lga == $list->lgaId) ? "selected" : ""}}>{{ $list->lga }}</option>
                                                        @endforeach
                                                    </select>
                                                    </div>
                                                </div>


                                                <div class="form-group m-form__group row">
                                                    <div class="col-md-4">
                                                    <!-- <input type="text" class="form-control m-input m-input--square" id="exampleInputEmail1" aria-describedby="emailHelp" placeholder="Enter email"> -->
                                                    <button type="submit" id="basicbtn" onclick="return submitStudentDetailInViewStudentPage();" disabled="disabled" class="btn btn-brand">&nbsp&nbsp Save <i class="fa fa-spinner fa-spin" style="display:none"></i>&nbsp&nbsp</button>
                                                    </div>

                                                </div>
                                            </div>

                                            </form>

onclick of the save button, ajax is firedup, this is the ajax

form = document.getElementById('basicinfoform');

formdata = new FormData(form);

console.log(formdata)
$.ajax({
    url : "/ajax/post/studentinfo",
    data: formdata,
    method: 'post',
    processData: false,
    contentType: false,
    success : function (res){
        if(res){
            console.log(res)

        }
    }
   });
return false;

here is my controller

public function viewStudent(Request $request, $studentid = null)
{


    if(!Auth::check()){
        return redirect('/');
    }

    if($request){
          echo 'yes';
    }
    if(!is_null($studentid)){

        $data['allstates']  = DB::table('tblstates')->get();
        $data['alllga'] = DB::table('tbl_lga')->get();
        $data['studentinfo'] = DB::table('tblstudents')
                                ->where('id', $studentid)
                                ->first();

        return view('Students.viewstudents', $data);
    }
    return redirect('/all/students');
}

in this controller, i have set a condition to check if request has been made so to make edit, so I simply echoed ‘Yes’ for the sake of testing and this question. Meaning my ajax response is simply suppose to be ‘Yes’ string literal, but below is what I get in the as response

 <!DOCTYPE html>

<!-- Required meta tags -->

--begin::Base Styles -->  

    <!--begin::Page Vendors -->

    <link href="http://127.0.0.1:8000/assets/vendors/custom/fullcalendar/fullcalendar.bundle.css" rel="stylesheet" type="text/css" />

    <!--end::Page Vendors -->

    <link href="http://127.0.0.1:8000/assets/vendors/base/vendors.bundle.css" rel="stylesheet" type="text/css" />

    <link href="http://127.0.0.1:8000/assets/demo/default/base/style.bundle.css" rel="stylesheet" type="text/css" />

<!-- <link rel="stylesheet" type="text/css" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css"> -->

    <!--end::Base Styles -->

    <link rel="shortcut icon" href="http://127.0.0.1:8000/assets/demo/default/media/img/logo/favicon.ico" />

<link rel="stylesheet" type="text/css" href="http://127.0.0.1:8000/DataTables/datatables.min.css"/>

    <link rel="stylesheet" type="text/css" href="http://127.0.0.1:8000/css/bootstrap.css"/>

Answer

I think it should look something like this

public function viewStudent(Request $request, $studentid = null)
{
    if(!Auth::check())
    {
        return redirect('/');
    }

    if($request)
    {
          // echo outputs to the server, but you should really return something
          // for the requester, thus we will return "YES" to the response
          // and since we are returning, it will return and no further executions will made.
          return 'yes';
    }

    if(!is_null($studentid))
    {

        $data['allstates']  = DB::table('tblstates')->get();
        $data['alllga'] = DB::table('tbl_lga')->get();
        $data['studentinfo'] = DB::table('tblstudents')
                                ->where('id', $studentid)
                                ->first();

        return view('Students.viewstudents', $data);
    }

    return redirect('/all/students');
}