글쓰기창에서 스크립트 작동이 안됩니다ㅠㅠ

<div class="form-group">
    <label class="col-sm-2 control-label-w" for="wr_1">선택<strong class="sound_only">필수</strong></label>
    <div class="col-sm-10">
        <div class="input-group" id="input_chk">

                <input type="text" name="wr_1" value="<?php echo $write['wr_1']; ?>" id="wr_1" required class="form-control input-sm" size="50" maxlength="255" ><br>
                <input type="checkbox" name="input" class="iput" value="A"> A
                <input type="checkbox" name="input" class="iput" value="B"> B
                <input type="checkbox" name="input" class="iput" value="C"> C
                <input type="checkbox" name="input" class="iput" value="D"> D
                <input type="checkbox" name="input" class="iput" value="E"> E
        </div>
    </div>
</div>
<script>
var cb = document.querySelectorAll('.iput');
var ip = document.getElementById('wr_1');
var val = [];
for(var i of cb){
i.addEventListener('change',(e)=>{
var cind = val.indexOf(e.target.name);
if(cind === -1){
val.push(e.target.name)
}else{
val.splice(cind,1)
}
ip.value = val.join(" | ")
})
}
</script>