[bes]

<input id="inp">
<div id='parent'>
   <div>
      <div>abc</div>
      <div>a</div>
      <div>b</div>
   </div>
   <div>
      <div>c</div>
      <div>d</div>
   </div>
</div>

<script>
window.onload = function() {//onload begin
   var inp = document.getElementById('inp');

  var find = function() {//find begin
    var parent = document.getElementById('parent');
    var divs = parent.getElementsByTagName('div');
    len = divs.length;

    for (var i = 0; i < len; i++) {//for begin
      if (divs[i].childNodes.length == 1 && inp.value != divs[i].innerHTML && inp.value != '') {
        divs[i].style.display = 'none'; 
      } else if (divs[i].style.display != 'block') {
        divs[i].style.display = 'block';
      }
    }//for end
        
  }//find end

  inp.onkeyup = function() {
    find();
  }
 
}//onload end
</script>