체크박스 (checkbox) 전체 값 구하기

<div class="dcp_group">
  <div class="dcp rd">
    <input type="checkbox" id="search_channel_00" value="" name="channels" data-group="channels" class="boardAllChecker" checked="checked">
    <label for="search_channel_00" ><span>전체</span></label>
  </div>
  <div class="dcp rd">
    <input type="checkbox" id="search_channel_01" value="스팸 카테고리" name="channels" data-group="channels" class="boardAllChecker" checked="checked">
    <label for="search_channel_01" ><span>스팸 카테고리</span></label>
  </div>	
  <div class="dcp rd">
    <input type="checkbox" id="search_channel_02" value="감성" name="channels" data-group="channels" class="boardAllChecker" checked="checked">
    <label for="search_channel_02" ><span>감성</span></label>
  </div>	
</div>

	// 수정 항목
	var channelArr = document.getElementsByName("channels");
	var selectedChannelArr = [];
	
	channelArr.forEach(function(channel){
		if(channel.checked == true && channel.value != "") selectedChannelArr.push(channel.value);
	});