search js

<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
      re='.*?';
p = new RegExp(re+inp.value,["i"]);
 m = p.exec(divs[i].innerHTML);
      if (divs[i].childNodes.length == 1 && m == null && 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>