function initializeFilters() {  // Bail early for Konqueror and IE5.2/Mac, which don't fully support dynamic  // creation of form controls  try {    var test = document.createElement("input");    test.type = "button";    if (test.type != "button") throw Error();  } catch (e) {    return;  }  // Removes an existing row from the filters table  function removeRow(button, propertyName) {    var tr = getAncestorByTagName(button, "tr");    var mode = null;    var selects = tr.getElementsByTagName("select");    for (var i = 0; i < selects.length; i++) {      if (selects[i].name == propertyName + "_mode") {        mode = selects[i];        break;      }    }    if (mode && (getAncestorByTagName(mode, "tr") == tr)) {      // Check whether there are more 'or' rows for this filter      var next = tr.nextSibling;      if (next && (next.className == propertyName)) {        function getChildElementAt(e, idx) {          e = e.firstChild;          var cur = 0;          while (cur <= idx) {            while (e && e.nodeType != 1) e = e.nextSibling;            if (cur++ == idx) break;            e = e.nextSibling;          }          return e;        }        var thisTh = getChildElementAt(tr, 0);        var nextTh = getChildElementAt(next, 0);        next.insertBefore(thisTh, nextTh);        nextTh.colSpan = 1;        thisTd = getChildElementAt(tr, 0);        nextTd = getChildElementAt(next, 1);        next.replaceChild(thisTd, nextTd);      }    }    var tBody = tr.parentNode;    tBody.deleteRow(tr.sectionRowIndex);    if (!tBody.rows.length) {        tBody.parentNode.removeChild(tBody);    }        if (propertyName) {      var select = document.forms["query"].elements["add_filter"];      for (var i = 0; i < select.options.length; i++) {        var option = select.options[i];        if (option.value == propertyName) option.disabled = false;      }    }  }  // Initializes a filter row, the 'input' parameter is the submit  // button for removing the filter  function initializeFilter(input) {    var removeButton = document.createElement("input");    removeButton.type = "button";    removeButton.value = input.value;    if (input.name.substr(0, 10) == "rm_filter_") {      removeButton.onclick = function() {        var endIndex = input.name.search(/_\d+$/);        if (endIndex < 0) endIndex = input.name.length;        removeRow(removeButton, input.name.substring(10, endIndex));        return false;      }    } else {      removeButton.onclick = function() {        removeRow(removeButton);        return false;      }    }    input.parentNode.replaceChild(removeButton, input);  }  // Make the submit buttons for removing filters client-side triggers  var filters = document.getElementById("filters");  var inputs = filters.getElementsByTagName("input");  for (var i = 0; i < inputs.length; i++) {    var input = inputs[i];    if (input.type == "submit" && input.name     && input.name.match(/^rm_filter_/)) {      initializeFilter(input);    }  }  // Make the drop-down menu for adding a filter a client-side trigger  var addButton = document.forms["query"].elements["add"];  addButton.parentNode.removeChild(addButton);  var select = document.getElementById("add_filter");  select.onchange = function() {    if (select.selectedIndex < 1) return;    if (select.options[select.selectedIndex].disabled) {      // Neither IE nor Safari supported disabled options at the time this was      // written, so alert the user      alert("A filter already exists for that property");      return;    }    // Convenience function for creating a <label>    function createLabel(text, htmlFor) {      var label = document.createElement("label");      if (text) label.appendChild(document.createTextNode(text));      if (htmlFor) label.htmlFor = htmlFor;      return label;    }    // Convenience function for creating an <input type="checkbox">    function createCheckbox(name, value, id) {      var input = document.createElement("input");      input.type = "checkbox";      if (name) input.name = name;      if (value) input.value = value;      if (id) input.id = id;      return input;    }    // Convenience function for creating an <input type="radio">    function createRadio(name, value, id) {      var input = document.createElement("input");      input.type = "radio";      if (name) input.name = name;      if (value) input.value = value;      if (id) input.id = id;      return input;    }    // Convenience function for creating a <select>    function createSelect(name, options, optional) {      var e = document.createElement("select");      if (name) e.name = name;      if (optional) e.options[0] = new Option();      if (options) {        for (var i = 0; i < options.length; i++) {          var option;          if (typeof(options[i]) == "object") {            option = new Option(options[i].text, options[i].value);          } else {            option = new Option(options[i], options[i]);          }          e.options[e.options.length] = option;        }      }      return e;    }    var propertyName = select.options[select.selectedIndex].value;    var property = properties[propertyName];    var table = document.getElementById("filters").getElementsByTagName("table")[0];    var tr = document.createElement("tr");    tr.className = propertyName;    var alreadyPresent = false;    for (var i = 0; i < table.rows.length; i++) {      if (table.rows[i].className == propertyName) {        var existingTBody = table.rows[i].parentNode;        alreadyPresent = true;        break;      }    }    // Add the row header    var th = document.createElement("th");    th.scope = "row";    if (!alreadyPresent) {      th.appendChild(createLabel(property.label));    } else {      th.colSpan = 2;      th.appendChild(createLabel("or"));    }    tr.appendChild(th);    var td = document.createElement("td");    if (property.type == "radio" || property.type == "checkbox") {      td.colSpan = 2;      td.className = "filter";      if (property.type == "radio") {        for (var i = 0; i < property.options.length; i++) {          var option = property.options[i];          td.appendChild(createCheckbox(propertyName, option,            propertyName + "_" + option));          td.appendChild(createLabel(option ? option : "none",            propertyName + "_" + option));        }      } else {        td.appendChild(createRadio(propertyName, "1", propertyName + "_on"));        td.appendChild(document.createTextNode(" "));        td.appendChild(createLabel("yes", propertyName + "_on"));        td.appendChild(createRadio(propertyName, "0", propertyName + "_off"));        td.appendChild(document.createTextNode(" "));        td.appendChild(createLabel("no", propertyName + "_off"));      }      tr.appendChild(td);    } else {      if (!alreadyPresent) {        // Add the mode selector        td.className = "mode";        var modeSelect = createSelect(propertyName + "_mode",                                      modes[property.type]);        td.appendChild(modeSelect);        tr.appendChild(td);      }      // Add the selector or text input for the actual filter value      td = document.createElement("td");      td.className = "filter";      if (property.type == "select") {        var element = createSelect(propertyName, property.options, true);      } else if (property.type == "text") {        var element = document.createElement("input");        element.type = "text";        element.name = propertyName;        element.size = 42;      }      td.appendChild(element);      element.focus();      tr.appendChild(td);    }    // Add the add and remove buttons    td = document.createElement("td");    td.className = "actions";    var removeButton = document.createElement("input");    removeButton.type = "button";    removeButton.value = "-";    removeButton.onclick = function() { removeRow(removeButton, propertyName) };    td.appendChild(removeButton);    tr.appendChild(td);    if (alreadyPresent) {      existingTBody.appendChild(tr);    } else {      // Find the insertion point for the new row. We try to keep the filter rows      // in the same order as the options in the 'Add filter' drop-down, because      // that's the order they'll appear in when submitted.      var insertionPoint = getAncestorByTagName(select, "tbody");      outer: for (var i = select.selectedIndex + 1; i < select.options.length; i++) {        for (var j = 0; j < table.tBodies.length; j++) {          if (table.tBodies[j].rows[0].className == select.options[i].value) {            insertionPoint = table.tBodies[j];            break outer;          }        }      }      // Finally add the new row to the table      var tbody = document.createElement("tbody");      tbody.appendChild(tr);      insertionPoint.parentNode.insertBefore(tbody, insertionPoint);    }    // Disable the add filter in the drop-down list    if (property.type == "radio" || property.type == "checkbox") {      select.options[select.selectedIndex].disabled = true;    }    select.selectedIndex = 0;  }}