将选项附加到使用ajax的多选中，并保持所选值

Question

我正在使用this multiSelect插件。

刀片模板

/tmp % gcc -pedantic -Wextra c.c
/tmp % cp c.c exercise1.txt
/tmp % ./a.out
#include<stdio.h>
#include<stdlib.h>

int main()
{
  FILE * fPointer = fopen("exercise1.txt","r");

  if (fPointer == NULL)
    puts("cannot open exercise1.txt");
  else {
    char singleline[150];

    while (fgets(singleline, sizeof(singleline), fPointer))
      fputs(singleline, stdout);

    fclose(fPointer);
  }

  return 0;
}
/tmp % \rm exercise1.txt 
/tmp % ./a.out
cannot open exercise1.txt

jQuery代码

<form method="POST" id="report-form" action="{{ route('admin.reports.store') }}" aria-label="{{ __('Create Report') }}">
                            {{ csrf_field() }}
                            <div class="row">
                                <div class="form-group col-md-6">
                                    <label class="control-label mb-10 text-left" for="tableName">Choose Table</label>
                                    <select class="form-control" name="tableName" id="tableName">
                                        <option>Choose</option>
                                        @foreach ( $tables as $table )
                                            <option value="{{ $table }}">{{ slugFormat($table) }}</option>
                                        @endforeach
                                    </select>
                                    @if ($errors->has('tableName'))
                                        <span class="invalid-feedback" role="alert">
                                            <strong>{{ $errors->first('tableName') }}</strong>
                                        </span>
                                    @endif
                                </div>
                                <div class="col-md-6">
                                    <label class="control-label mb-10 text-left" for="columns">Select Column</label>
                                    <select class="form-control" name="columns[]" id="columns">
                                        <option>Choose</option>
                                    </select>

                                    @if ($errors->has('column'))
                                        <span class="invalid-feedback" role="alert">
                                           <strong>{{ $errors->first('column') }}</strong>
                                        </span>
                                    @endif
                                </div>
                             </div>
                             <div class="row">
                                <div class="col-md-12">
                                    <div class="form-group mb-0 pull-right">
                                        <button name="submit" type="submit" class="btn btn-primary">submit</button>
                                    </div>
                                </div>
                                </div>
                        </form>

当我更改表选择时，我会在#columns选择框中获取属于该表的列，现在，如果我从#columns Seelect框中选择某些列并更改表，那么它也在清除所选值，我需要检查来自多个表的多个列。

Github Code显示了插件的基本实现。