selectbox 셀렉트 박스 필수 required 를 적용했는데 안됩니다. 채택완료

<form name=frm method=post action="<?=G5_BBS_URL;?>/write_update_quick.php">		<input type=hidden name=w        value="">		<input type=hidden name=bo_table value="landing">		<input type=hidden name=wr_id    value="">		<input type=hidden name=sca      value="<?=$sca?>">		<input type=hidden name=sfl      value="">		<input type=hidden name=stx      value="">		<input type=hidden name=spt      value="">		<input type=hidden name=sst      value="">		<input type=hidden name=sod      value="">		<input type=hidden name=secret value='secret' />		<input type=hidden name=s    value="s">		<input type=hidden name=wr_key    value="<?=$norobot_key?>"> 		<input type=hidden name=page     value="<?=$page?>">		<input type=hidden name="wr_subject" value="실시간 빠른 상담이 접수되었습니다.">		<input type=hidden name="wr_content" value="내용">			<div class="from_box">				<h1 class="logo">					<a href="#" target="_blank"></a>				</h1>				<div class="from_content">					<input type="text" id="wr_name" name="wr_name" required placeholder="이름" class="input_st1" maxlength="4"/>					<input type="text" id="wr_1" name="wr_1" required placeholder="전화번호" class="input_st2" maxlength="15"/>					<select required name="wr_2" id="wr_2" class="select_list" >						<option >이벤트선택</option>						<option value="옵션1"  >옵션1</option>						<option value="옵션2"  >옵션2</option>						<option value="옵션3"  >옵션3</option>					</select>					<div class="cle"></div>					<label class="ck_box">						<input name="wr_6" type="checkbox" checked id="wr_6" required > 개인정보 취급방침 동의					</label>				</div>				<button class="landing_bt"></button>			</div> <!--//  from_box -->		</form>