My first javascript: a list filter

My list of publications is getting too long to browse conveniently. I wrote this client-side script to filter by substring matches.

// filterlists.js
//
//  In every <ol> of the document, hides list items that don't match the criteria
//  in the remaining lines, highlight the matches
//
//  To use, add
//    <input onkeyup = "filter(this.value)" />  in the document's body
//    <script type="text/javascript" src="filterlists.js"></script> in the document's head
//    span.highlighted {background-color: #00FFFF} in the document's css
//
// Copyleft GPL v3, Minh Ha-Duong, CIRED, 2008.

function filter(criteria) {
  categories = document.getElementsByTagName("ol")
  for (j=0; j<categories.length; j++) {
    filterList(criteria, categories[j])
  }
}

function filterList(searchString, textContainerNode) {
 var tempinnerHTML = textContainerNode.innerHTML

  // Unlight all
 var regex = new RegExp('<span class="highlighted">([^>]*)?</span>',"ig")
 tempinnerHTML = tempinnerHTML.replace(regex,'$1')

 // Highlight matching spans
 regex = new RegExp(">([^<]*)?("+searchString+")([^>]*)?<","ig")
 textContainerNode.innerHTML = tempinnerHTML.replace(regex,'>$1<span class="highlighted">$2</span>$3<');

// Hide nonmatching list items
 regexp = new RegExp(searchString,"i")
 var allitems = textContainerNode.getElementsByTagName("li")
 for (i=0 ; i<allitems.length; i++) {
   rawtext = allitems[i].innerHTML.replace(/<[^>]*>/g,"").replace(/\(Abstract\)/,"")
   allitems[i].style.display = (rawtext.match(regexp) ? 'block' : 'none')
 }
}