숫자만 입력하기.

function chk(event){
  ev = window.event || event;
  
  if((ev.keyCode>=48 && ev.keyCode<=57) || ev.keyCode == "8" ) return true;
  else return false;
  }

<input type="text" name="crn1" id="ID_TB04_crn1" maxlength="3" onkeypress="return chk();" style="width: 15%;ime-mode:disabled" />-