This is a function to check if input data only contains numeric values

<input type="text" class="form-control" placeholder="Search &amp; enter" id='dtablesearch' onkeyup="searchcollum()"/>

const searchcollum = () =>{
    let filter = document.getElementById('dtablesearch').value.toUpperCase();
    if (/^\d+$/.test(filter)==true){
              let dtable = document.getElementById('zero_config');
              let tr = document.getElementsByTagName('tr');
              for (var i=0; i<tr.length; i++){
                let td = tr[i].getElementsByTagName('td')[2];
                if (td){
                  let txtvalue = td.textContent || td.innerHTML;
                  if (txtvalue.toUpperCase().indexOf(filter)>-1){
                    tr[i].style.display = "";
                  }else{
                    tr[i].style.display = "None";
                  }
                }
              }
           }
        }

Condition isn't getting True as result even when I enter 16 in the input...

Any suggestions ??