ankiweb_filter_tweak.user.js

// ==UserScript==
// @match http://ankiweb.net/*
// @match https://ankiweb.net/*
// ==/UserScript==

function addJQuery(callback) {
  var script = document.createElement("script");
  script.setAttribute("src", "https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js");
  script.addEventListener('load', function() {
    var script = document.createElement("script");
    script.textContent = "window.jQ=jQuery.noConflict(true);(" + callback.toString() + ")();";
    document.body.appendChild(script);
  }, false);
  document.body.appendChild(script);
}

// the guts of this userscript
function main() {
  // Note, jQ replaces $ to avoid conflicts.
  $(document).ready(function(){setTimeout(function(){
    $('#list').prepend(
      '<div class="form-group">'+
        '<label class="control-label" for="list_filter">Filter</label>&nbsp;'+  
        '<input name="list_filter" id="list_filter"></input>'+
      '</div>')
    var input_counter = 0
    $('#list_filter').on('input',function() {
        var my_input_event = ++input_counter
        setTimeout(function(){
          if (my_input_event === input_counter) {
            var input_toks = $('#list_filter').val().replace(/(^\s+|\s+$)/,'').split()
            $('#list tr').each(function(idx,tr) {
                if (idx === 0) { // first result is header
                  return
                }
                for (var i=0; i < input_toks.length; ++i) {
                  if (input_toks[i] && !RegExp(input_toks[i],'i').test(tr.innerText)) {
                    tr.style.display = 'none'
                    return
                  }
                }
                tr.style.display = 'table-row'
            })
          }
        },300)
    })
        
  },500)})
}

// load jQuery and execute the main function
addJQuery(main);