bootstrap custom select option style code example

Example 1: bootstrap select input

<div class="form-group">
    <label for="exampleFormControlSelect1">Example select</label>
    <select class="form-control" id="exampleFormControlSelect1">
      <option>1</option>
      <option>2</option>
      <option>3</option>
      <option>4</option>
      <option>5</option>
    </select>
  </div>
  <div class="form-group">
    <label for="exampleFormControlSelect2">Example multiple select</label>
    <select multiple class="form-control" id="exampleFormControlSelect2">
      <option>1</option>
      <option>2</option>
      <option>3</option>
      <option>4</option>
      <option>5</option>
    </select>
  </div>

Example 2: selectpicker dropdown in bootsttrap

<select class="selectpicker" required multiple>
  <optgroup label="Picnic">
    <option>Mustard</option>
    <option>Ketchup</option>
    <option>Relish</option>
  </optgroup>
  <optgroup label="Camping">
    <option>Tent</option>
    <option>Flashlight</option>
    <option>Toilet Paper</option>
  </optgroup>
</select>