在jQuery和Laravel中执行ajax调用时，哪个值是非法的

Question

我正在尝试通过JQuery的Ajax函数提交表单但是我得到的状态为0，而eTe statText表示＆＃34; [例外...＆＃34;非法值＆＃34; nsresult：＆＃34; 0x80070057（NS_ERROR_ILLEGAL_VALUE）＆＃34; location：＆＃34; JS frame :: https://code.jquery.com/jquery.js :: .send :: line 9592＆＃34;数据：没有]＆＃34;＆＃34;它告诉我没有数据，但是当我在console.log时，它看起来是正确的数据。我希望有人可以告诉我我做错了什么，哪个价值是非法的

//ajax code
$.ajax({
            type: ':post',
            url: 'districts/add',
            dataType: 'json',
            data: $('#add_district_form').serialize(),
            success: function(response){
                console.log('success');
            },
            error: function (xhr, desc, err) {
                console.log('AJAX didn\'t load');
                console.log(xhr);
                console.log(desc);
                console.log(err);
            }
        });

 //form
 <form id="add_district_form">
                    <div class="row">
                        <div class="col-md-8">
                            <input type="text" class="broker-form" id="DistrictName" name=DistrictName" placeholder="District Name" required="required">
                        </div>
                        <div class="col-md-4">
                            <input type="text" class="broker-form" id="DistrictId" name="DistrictId" placeholder="District ID" required="required">
                        </div>
                    </div>
                    <div class="row">
                        <div class="col-md-4"><input type="text" class="broker-form" id="Address" name="Address" placeholder="Address">
                        </div>
                        <div class="col-md-4"><input type="text" class="broker-form" id="City" name="City" placeholder="City">
                        </div>
                        <div class="col-md-2"><input type="text" class="broker-form" id="State" name="State" placeholder="State">
                        </div>
                        <div class="col-md-2">
                            <input type="text" class="broker-form" id="Zip" name="Zip" placeholder="ZIP">
                        </div>
                    </div>
                    <div class="row">
                        <div class="col-md-4">
                            <input type="text" class="broker-form" id="ContactName" name="ContactName" placeholder="Contact Name"></div>
                        <div class="col-md-4">
                            <input type="text" class="broker-form" id="ContactEmail" name="ContactEmail" placeholder="Contact Email"></div>
                        <div class="col-md-4">
                            <input type="text" class="broker-form" id="ContactPhone" name="ContactPhone" placeholder="Contact Phone"></div>
                    </div>
                    <p class="text-right"><a class="btn btn-sm btn-red" href="#" data-dismiss="modal">Close</a>
                        <a class="btn btn-sm btn-green" id="add_district_submit" href="#">Submit</a>
                    </p>
                </form>