diff --git a/instances/templates/allinstances.html b/instances/templates/allinstances.html
index 52aff586..835fd56f 100644
--- a/instances/templates/allinstances.html
+++ b/instances/templates/allinstances.html
@@ -12,6 +12,14 @@
     {% include 'create_inst_block.html' %}
 {% endif %}
     {% include 'search_block.html' %}
+    <div class="float-end search">
+        <select id="state-filter" class="form-select" aria-label="{% trans 'State' %}">
+            <option value="">{% trans 'All states' %}</option>
+            {% for state in states %}
+                <option>{{ state }}</option>
+            {% endfor %}
+        </select>
+    </div>
 {% endblock page_heading_extra %}
 
 {% block content %}
@@ -40,7 +48,7 @@
 {% endblock content %}
 {% block script %}
     <script src="{% static 'js/sortable.min.js' %}"></script>
-    <script src="{% static 'js/filter-table.js' %}"></script>
+    <script src="{% static 'js/instance_filter.js' %}"></script>
     {% if request.user.is_superuser %}
         <script>
             // The new-VM dialog's CPU bars: each compute's load over one second,
diff --git a/instances/templates/allinstances_index_grouped.html b/instances/templates/allinstances_index_grouped.html
index 95ef5472..386672c7 100644
--- a/instances/templates/allinstances_index_grouped.html
+++ b/instances/templates/allinstances_index_grouped.html
@@ -17,7 +17,7 @@
             </tr>
         </thead>
         {% for compute in computes %}
-            <tbody class="searchable">
+            <tbody class="searchable" data-host="{{ compute.name }}">
                 {% if compute.instance_set.count > 0 %}
                     <tr class="table-secondary fw-bold border-bottom border-dark">
                         <td>
@@ -97,17 +97,15 @@
 
 {% block script %}
 <script>
+// a collapsed host's VM rows are hidden by its table body's class, so the
+// search (instance_filter.js, the hidden attribute) can still hide them too
 function hide_all_host_instances() {
-    var rows = $('table tr');
-    all_host_rows = rows.filter('[host]');
-    all_host_rows.toggle();
+    $('tbody.searchable').toggleClass('host-collapsed');
     $('span[id^=collapse_host_instances_]').toggleClass("bi bi-chevron-down ").toggleClass("bi bi-chevron-up");
     $('span[id^=inst_count_badge_]').toggleClass("d-none");
 }
 function hide_host_instances(host) {
-    var rows = $('table tr');
-    host_rows = rows.filter("[host='"+host+"']");
-    host_rows.toggle();
+    $("span[id='collapse_host_instances_"+host+"']").closest('tbody').toggleClass('host-collapsed');
     $("span[id='collapse_host_instances_"+host+"']").toggleClass("bi bi-chevron-down ").toggleClass("bi bi-chevron-up");
     $("span[id='inst_count_badge_"+host+"']").toggleClass("d-none");
 }
diff --git a/instances/templates/instance_state.html b/instances/templates/instance_state.html
index 20c99385..8f603d11 100644
--- a/instances/templates/instance_state.html
+++ b/instances/templates/instance_state.html
@@ -1,3 +1,3 @@
 {% load vm_states %}
 {% if instance.info %}{% vm_state instance.info.0 as state %}{% else %}{% vm_state None as state %}{% endif %}
-<span class="text-{{ state.1 }}">{{ state.0 }}</span>
+<span class="text-{{ state.1 }}" data-state="{{ state.0 }}">{{ state.0 }}</span>
diff --git a/instances/tests/js/instance_filter.test.js b/instances/tests/js/instance_filter.test.js
new file mode 100644
index 00000000..b3b67d19
--- /dev/null
+++ b/instances/tests/js/instance_filter.test.js
@@ -0,0 +1,51 @@
+// node instance_filter.test.js path/to/static/js/instance_filter.js
+const assert = require("assert");
+const {filterInstances} = require(process.argv[2]);
+
+// A minimal DOM: table bodies of rows; a VM row holds its state mark.
+function vm(text, state) {
+    const mark = {dataset: {state}};
+    return {textContent: text, hidden: false, querySelector: (s) => (s === "[data-state]" ? mark : null)};
+}
+function hostRow(text) {
+    return {textContent: text, hidden: false, querySelector: () => null};
+}
+function group(rows, host) {
+    return {dataset: host ? {host} : {}, querySelectorAll: (s) => (s === "tr" ? rows : [])};
+}
+function page(groups, text, state) {
+    const inputs = {filter: {value: text}, "state-filter": {value: state}};
+    return {
+        getElementById: (id) => inputs[id],
+        querySelectorAll: (s) => (s === ".searchable" ? groups : []),
+    };
+}
+const visible = (rows) => rows.filter((r) => !r.hidden).map((r) => r.textContent);
+
+// the flat list: search and state together
+let rows = [vm("web-1 Active", "Active"), vm("inactive-db Off", "Off"), vm("Web-2 Off", "Off")];
+filterInstances(page([group(rows)], "", ""));
+assert.deepStrictEqual(visible(rows), ["web-1 Active", "inactive-db Off", "Web-2 Off"], "no filter shows all");
+filterInstances(page([group(rows)], "WEB", ""));
+assert.deepStrictEqual(visible(rows), ["web-1 Active", "Web-2 Off"], "search ignores case");
+filterInstances(page([group(rows)], "", "Active"));
+assert.deepStrictEqual(visible(rows), ["web-1 Active"], "state is the VM's, not a word in its name");
+filterInstances(page([group(rows)], "web", "Off"));
+assert.deepStrictEqual(visible(rows), ["Web-2 Off"], "both apply");
+filterInstances(page([group(rows)], "web-1 (", ""));
+assert.deepStrictEqual(visible(rows), [], "the search is text, not a pattern");
+
+// the grouped list: a host row shows while any of its VMs does
+const header1 = hostRow("host-a Connected"), a = [header1, vm("web-1 Active", "Active"), vm("db-1 Off", "Off")];
+const header2 = hostRow("host-b Connected"), b = [header2, vm("web-9 Off", "Off")];
+const groups = [group(a, "host-a"), group(b, "host-b")];
+filterInstances(page(groups, "db", ""));
+assert.deepStrictEqual(visible(a), ["host-a Connected", "db-1 Off"]);
+assert.deepStrictEqual(visible(b), [], "a host without a match is hidden");
+filterInstances(page(groups, "HOST-B", ""));
+assert.deepStrictEqual(visible(b), ["host-b Connected", "web-9 Off"], "a host's name shows all its VMs");
+assert.deepStrictEqual(visible(a), []);
+filterInstances(page(groups, "host-a", "Off"));
+assert.deepStrictEqual(visible(a), ["host-a Connected", "db-1 Off"], "the state applies to a host's VMs too");
+filterInstances(page(groups, "Connected", ""));
+assert.deepStrictEqual(visible(a), [], "a host row's other text is not its name");
diff --git a/instances/tests/test_instance_filter_js.py b/instances/tests/test_instance_filter_js.py
new file mode 100644
index 00000000..90621652
--- /dev/null
+++ b/instances/tests/test_instance_filter_js.py
@@ -0,0 +1,23 @@
+"""The instance list's search box and state list (static/js/instance_filter.js).
+Its behaviour is checked with Node."""
+
+import shutil
+import subprocess
+import unittest
+from pathlib import Path
+
+from django.conf import settings
+
+BASE = Path(settings.BASE_DIR)
+
+
+class InstanceFilterTestCase(unittest.TestCase):
+    @unittest.skipUnless(shutil.which("node"), "node is not installed")
+    def test_instance_filter_js(self):
+        result = subprocess.run(
+            ["node", str(BASE / "instances/tests/js/instance_filter.test.js"), str(BASE / "static/js/instance_filter.js")],
+            capture_output=True,
+            text=True,
+            timeout=60,
+        )
+        self.assertEqual(result.returncode, 0, result.stderr)
diff --git a/instances/tests/test_list_unreachable.py b/instances/tests/test_list_unreachable.py
index c9045329..e3708ec0 100644
--- a/instances/tests/test_list_unreachable.py
+++ b/instances/tests/test_list_unreachable.py
@@ -10,6 +10,7 @@ from django.contrib.auth import get_user_model
 from django.test import TestCase
 from django.urls import reverse
 from instances.models import Instance
+from lxml import html
 from vrtManager.util import OperationError
 
 ERROR = "Connection Failed: No route to host"
@@ -69,7 +70,8 @@ class UnreachableListTests(TestCase):
             self.assertContains(response, vm.name)
             self.assertNotContains(response, reverse("instances:poweron", args=[vm.id]))
             self.assertNotContains(response, reverse("instances:poweroff", args=[vm.id]))
-        self.assertContains(response, "Unknown", count=len(instances))
+        states = html.fromstring(response.content).xpath("//span[@data-state]/@data-state")
+        self.assertEqual(states.count("Unknown"), len(instances))
 
     def test_nongrouped_index_lists_the_vms_of_a_down_host(self):
         AppSettings.objects.filter(key="VIEW_INSTANCES_LIST_STYLE").update(value="nongrouped")
diff --git a/instances/tests/test_states.py b/instances/tests/test_states.py
index 6654415d..8698f9e8 100644
--- a/instances/tests/test_states.py
+++ b/instances/tests/test_states.py
@@ -119,6 +119,16 @@ class StateTests(TestCase):
                 self.assertEqual(self.offered(page, vm), set())
 
 
+    def test_the_list_offers_each_state_and_marks_each_row_and_host(self):
+        # static/js/instance_filter.js filters by these (test_instance_filter_js)
+        AppSettings.objects.filter(key="VIEW_INSTANCES_LIST_STYLE").update(value="grouped")
+        page = html.fromstring(self.get(self.admin, reverse("instances:index")))
+        options = page.xpath("//select[@id='state-filter']/option/text()")
+        self.assertEqual(options, ["All states", *LABELS.values(), "Unknown"])
+        marks = page.xpath("//tbody[@data-host='st']//tr//@data-state")
+        self.assertEqual(marks, list(LABELS.values()))
+
+
 class DetailStateTests(TestCase):
     """The VM page names every state and offers a forced power off where only that helps."""
 
diff --git a/instances/views.py b/instances/views.py
index 46643774..6ad9ef82 100755
--- a/instances/views.py
+++ b/instances/views.py
@@ -53,6 +53,7 @@ from instances.models import Instance
 from . import utils
 from .forms import ConsoleForm, FlavorForm, NewVMForm
 from .models import Flavor
+from .states import STATES, UNKNOWN
 
 # the VM page waits this long (seconds) for the compute's drbdadm status
 DRBD_STATUS_TIMEOUT = 10
@@ -85,7 +86,8 @@ def index(request):
         request,
         "allinstances.html",
         {"computes": computes, "instances": instances, "show_hosts": show_hosts, "own_hosts_down": own_hosts_down,
-         "reachable_computes": [c for c in computes if c.status is True]},
+         "reachable_computes": [c for c in computes if c.status is True],
+         "states": [label for label, _color in STATES.values()] + [UNKNOWN[0]]},
     )
 
 
diff --git a/static/css/webvirtcloud.css b/static/css/webvirtcloud.css
index 279dfca9..5ccf795e 100644
--- a/static/css/webvirtcloud.css
+++ b/static/css/webvirtcloud.css
@@ -53,6 +53,10 @@ body {
     height: 350px;
 }
 
+.host-collapsed tr[host] {
+    display: none;
+}
+
 .search {
     margin: 5px;
 }
diff --git a/static/js/instance_filter.js b/static/js/instance_filter.js
new file mode 100644
index 00000000..4201907c
--- /dev/null
+++ b/static/js/instance_filter.js
@@ -0,0 +1,43 @@
+// The instance list's search box and state list.
+//
+// A VM row shows when its text contains the search, in any case, and the VM is
+// in the chosen state. In the grouped list a search for a host's name shows
+// all of its VMs, and the host's row shows while any of its VMs does.
+function filterInstances(doc) {
+    var text = doc.getElementById("filter").value.toLowerCase();
+    var state = doc.getElementById("state-filter").value;
+    doc.querySelectorAll(".searchable").forEach(function (group) {
+        var host = group.dataset.host;
+        var hostMatches = host !== undefined && host.toLowerCase().includes(text);
+        var header = null, shown = false;
+        group.querySelectorAll("tr").forEach(function (row) {
+            var mark = row.querySelector("[data-state]");
+            if (!mark) {
+                header = row;
+                return;
+            }
+            row.hidden = !((!state || mark.dataset.state === state) &&
+                (hostMatches || row.textContent.toLowerCase().includes(text)));
+            shown = shown || !row.hidden;
+        });
+        if (header) {
+            header.hidden = !shown;
+        }
+    });
+}
+
+if (typeof module !== "undefined") {
+    module.exports = {filterInstances: filterInstances};
+} else {
+    // the search is remembered for a day, as on the other lists
+    var search = document.getElementById("filter");
+    search.value = Cookies.get(document.title + "_filter") || "";
+    search.addEventListener("input", function () {
+        Cookies.set(document.title + "_filter", search.value, {expires: 1});
+        filterInstances(document);
+    });
+    document.getElementById("state-filter").addEventListener("change", function () {
+        filterInstances(document);
+    });
+    filterInstances(document);
+}