diff --git a/AGENTS.md b/AGENTS.md
index 56fa49e..34f42a0 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -29,7 +29,7 @@ Last verified in the Nix shell on PHP 8.5.6 / Node 24.16.0:
 - `composer test`: 95 tests, 268 assertions.
 - `composer phpstan`: no errors.
 - `composer coverage`: PHP line coverage ~97%, threshold `80%`.
-- `npm run test:unit`: Jest 608 tests.
+- `npm run test:unit`: Jest 615 tests.
 - `npm run test:coverage`: JavaScript line coverage ~95%, threshold `80%`.
 - `npm test`: the above plus the Cypress e2e suite, 24 tests.
 
diff --git a/src/Resources/doc/2_3.md b/src/Resources/doc/2_3.md
index 6caf9bf..5f05cff 100644
--- a/src/Resources/doc/2_3.md
+++ b/src/Resources/doc/2_3.md
@@ -48,11 +48,44 @@ init_js_validation(form = null, onLoad = true, wrapped = true)
 - `form`: By default, all queued forms are processed. Pass a form name or
   `FormView` instance to process only one form.
 - `onLoad`: When `true`, validation models are initialized on document ready.
-  Pass `false` when you want to initialize them yourself.
+  Pass `false` when you want to initialize them yourself. A model rendered into
+  a document that already finished loading - a form fragment an application
+  fetched and injected after the initial load - is initialized right away,
+  because the document ready event it would otherwise wait for has already been
+  dispatched.
 - `wrapped`: When `true`, the generated code is wrapped in a
   `<script type="text/javascript">...</script>` tag.
 
-For example, to initialize validation after an Ajax request:
+#### Forms loaded after the page
+
+A form fragment the application fetches and injects - a modal that loads its
+form, a step of a wizard, a single page CRUD - carries the `addModel()` call
+the bundle rendered with it, and that call initializes the form as soon as it
+runs. The default `onLoad` is enough, there is nothing to pass:
+
+```twig
+{{ form(user) }}
+{{ init_js_validation(user) }}
+```
+
+The one thing the application has to take care of is that the call runs at
+all. `innerHTML` does not execute a `<script>` tag it inserts, so a fragment
+dropped in that way is rendered without ever being initialized. Insert it with
+something that runs the scripts it contains - jQuery's `.html()`, Turbo, or
+recreating the `<script>` nodes by hand - and make sure the form is in the
+document by then, because the model looks its nodes up there.
+
+A render that is taken out of the document again is forgotten the next time the
+same form is initialized, so reopening a modal does not pile up instances in
+`SvarohJsFormValidator.getFormInstances()`.
+
+The library has to be loaded and `js_validator_config()` rendered before any of
+this, which the layout does once.
+
+#### Initializing the models yourself
+
+To initialize the queued models at a moment of your own choosing, pass
+`onLoad = false`:
 
 ```twig
 {{ form(user) }}
diff --git a/src/Resources/doc/3_20.md b/src/Resources/doc/3_20.md
index afc321c..29c82f8 100644
--- a/src/Resources/doc/3_20.md
+++ b/src/Resources/doc/3_20.md
@@ -33,6 +33,11 @@ rows[2].children.name.onValidate = function (errors) {
 
 `SvarohJsFormValidator.forms['profile']` keeps the last initialized render.
 
+A render the application takes out of the document again - a modal that is
+closed, a row a listing replaces - is dropped from the list the next time the
+same form is initialized, so a page that reloads its forms does not accumulate
+instances of nodes that are gone.
+
 Forms of the same name repeat their ids, which is not valid HTML and hides all
 but the first render from `document.getElementById()` in your own scripts. If
 you can name the forms yourself, give each row a name of its own:
diff --git a/src/Resources/public/js/SvarohJsFormValidator.js b/src/Resources/public/js/SvarohJsFormValidator.js
index 8e4adc0..7a84ef2 100644
--- a/src/Resources/public/js/SvarohJsFormValidator.js
+++ b/src/Resources/public/js/SvarohJsFormValidator.js
@@ -651,10 +651,19 @@ var SvarohJsFormValidator = new function () {
         }
 
         var instances = this.formInstances[model.id];
-        for (var i = 0; i < instances.length; i++) {
+        // A single page application that swaps a rendered form for a new one
+        // leaves the element of the node it removed behind, and every reopened
+        // modal or revisited wizard step would add one more
+        for (var i = instances.length - 1; i >= 0; i--) {
+            if (this.isDetachedNode(instances[i].domNode)) {
+                instances.splice(i, 1);
+            }
+        }
+
+        for (var j = 0; j < instances.length; j++) {
             // A repeated initialization of the same markup replaces its element
-            if (instances[i].domNode && instances[i].domNode === element.domNode) {
-                instances[i] = element;
+            if (instances[j].domNode && instances[j].domNode === element.domNode) {
+                instances[j] = element;
 
                 return element;
             }
@@ -665,6 +674,22 @@ var SvarohJsFormValidator = new function () {
         return element;
     };
 
+    /**
+     * Whether the node was taken out of the document again, which only a
+     * browser that can answer it at all reports
+     *
+     * @param {HTMLElement|null} domNode
+     *
+     * @return {boolean}
+     */
+    this.isDetachedNode = function (domNode) {
+        if (!domNode || typeof document.contains !== 'function') {
+            return false;
+        }
+
+        return !document.contains(domNode);
+    };
+
     /**
      * All the elements initialized for the given model id, in the order they
      * were added
@@ -678,14 +703,38 @@ var SvarohJsFormValidator = new function () {
     };
 
     this.onDocumentReady = function (callback) {
+        // A model added to a document that is already loaded - a form fragment
+        // that a single page application fetched and injected - would wait
+        // here for an event that has already been dispatched. Only "complete"
+        // stands for that: while the state is "interactive" the document is
+        // parsed but its deferred scripts, and the js_validator_config() one
+        // of them may carry, still run before the event
+        if ('complete' === document.readyState) {
+            callback();
+
+            return;
+        }
+
+        var isFallback = !document.addEventListener;
         var addListener = document.addEventListener || document.attachEvent;
         var removeListener = document.removeEventListener || document.detachEvent;
-        var eventName = document.addEventListener ? "DOMContentLoaded" : "onreadystatechange";
+        var eventName = isFallback ? "onreadystatechange" : "DOMContentLoaded";
+
+        // The handler has to name itself to be removed again: the first
+        // argument a listener receives is the event, and "attachEvent" passes
+        // no argument at all, so neither identifies the function to detach
+        var handler = function () {
+            // The fallback listens to every state transition, only the last
+            // one stands for a document that finished loading
+            if (isFallback && 'complete' !== document.readyState) {
+                return;
+            }
 
-        addListener.call(document, eventName, function (callee) {
-            removeListener.call(this, eventName, callee, false);
+            removeListener.call(document, eventName, handler, false);
             callback();
-        }, false)
+        };
+
+        addListener.call(document, eventName, handler, false)
     };
 
     /**
diff --git a/src/Resources/public/js/SvarohJsFormValidator.test.js b/src/Resources/public/js/SvarohJsFormValidator.test.js
index c36ba02..46859a1 100644
--- a/src/Resources/public/js/SvarohJsFormValidator.test.js
+++ b/src/Resources/public/js/SvarohJsFormValidator.test.js
@@ -1223,6 +1223,7 @@ describe('SvarohJsFormValidator runtime helpers', () => {
 describe('SvarohJsFormValidator model registration', () => {
     afterEach(() => {
         document.body.innerHTML = '';
+        window.SvarohJsFormValidator.config = {};
         window.SvarohJsFormValidator.forms = {};
         window.SvarohJsFormValidator.formInstances = {};
         window.SvarohJsFormValidator.constraintsCounter = 0;
@@ -1242,6 +1243,21 @@ describe('SvarohJsFormValidator model registration', () => {
         };
     }
 
+    // jsdom reports "complete" for the whole run, a test of the deferred
+    // branch has to say the document is still loading itself
+    function withReadyState(state, run) {
+        Object.defineProperty(document, 'readyState', {
+            configurable: true,
+            get: () => state,
+        });
+
+        try {
+            run();
+        } finally {
+            delete document.readyState;
+        }
+    }
+
     test('skips a model whose form is not rendered on the current page', () => {
         document.body.innerHTML = '<form id="profile"><input id="profile_email" name="profile[email]"></form>';
         const missing = buildModel('ghost', 'ghost');
@@ -1264,18 +1280,139 @@ describe('SvarohJsFormValidator model registration', () => {
     });
 
     test('skips a model without a DOM node on the deferred branch too', () => {
-        document.body.innerHTML = '<form id="profile"><input id="profile_email" name="profile[email]"></form>';
-        const rendered = buildModel('profile', 'profile', {
-            email: buildModel('profile_email', 'profile[email]'),
+        withReadyState('loading', () => {
+            document.body.innerHTML = '<form id="profile"><input id="profile_email" name="profile[email]"></form>';
+            const rendered = buildModel('profile', 'profile', {
+                email: buildModel('profile_email', 'profile[email]'),
+            });
+
+            window.SvarohJsFormValidator.addModel(buildModel('ghost', 'ghost'));
+            window.SvarohJsFormValidator.addModel(rendered);
+
+            expect(window.SvarohJsFormValidator.forms.profile).toBeUndefined();
+
+            expect(() => document.dispatchEvent(new Event('DOMContentLoaded'))).not.toThrow();
+            expect(Object.keys(window.SvarohJsFormValidator.forms)).toEqual(['profile']);
+            expect(window.SvarohJsFormValidator.forms.profile.domNode).toBe(document.getElementById('profile'));
         });
+    });
 
-        window.SvarohJsFormValidator.addModel(buildModel('ghost', 'ghost'));
-        window.SvarohJsFormValidator.addModel(rendered);
+    // A single page application injects a form long after "DOMContentLoaded",
+    // and a listener for that event would never be called again
+    test('registers a model of a form injected after the document is ready', () => {
+        document.body.innerHTML = '<form id="profile"><input id="profile_email" name="profile[email]"></form>';
+
+        window.SvarohJsFormValidator.addModel(buildModel('profile', 'profile', {
+            email: buildModel('profile_email', 'profile[email]'),
+        }));
 
-        expect(() => document.dispatchEvent(new Event('DOMContentLoaded'))).not.toThrow();
         expect(Object.keys(window.SvarohJsFormValidator.forms)).toEqual(['profile']);
         expect(window.SvarohJsFormValidator.forms.profile.domNode).toBe(document.getElementById('profile'));
     });
+
+    test('still waits for the document while it is being parsed', () => {
+        withReadyState('loading', () => {
+            document.body.innerHTML = '<form id="profile"><input id="profile_email" name="profile[email]"></form>';
+            window.SvarohJsFormValidator.addModel(buildModel('profile', 'profile', {
+                email: buildModel('profile_email', 'profile[email]'),
+            }));
+
+            expect(window.SvarohJsFormValidator.forms.profile).toBeUndefined();
+
+            document.dispatchEvent(new Event('DOMContentLoaded'));
+
+            expect(window.SvarohJsFormValidator.forms.profile.domNode).toBe(document.getElementById('profile'));
+        });
+    });
+
+    // A deferred script runs after the parse but before "DOMContentLoaded",
+    // and js_validator_config() may be one of the scripts still to come
+    test('still waits for the document while its deferred scripts run', () => {
+        withReadyState('interactive', () => {
+            document.body.innerHTML = '<form id="profile"><input id="profile_email" name="profile[email]"></form>';
+            window.SvarohJsFormValidator.addModel(buildModel('profile', 'profile', {
+                email: buildModel('profile_email', 'profile[email]'),
+            }));
+
+            expect(window.SvarohJsFormValidator.forms.profile).toBeUndefined();
+
+            document.dispatchEvent(new Event('DOMContentLoaded'));
+
+            expect(window.SvarohJsFormValidator.forms.profile.domNode).toBe(document.getElementById('profile'));
+        });
+    });
+
+    // The configuration a template prints below the model decides whether the
+    // native UI is turned off, so the call waiting for it must not run early
+    test('turns the native UI off with a configuration a deferred script sets', () => {
+        withReadyState('interactive', () => {
+            document.body.innerHTML = '<form id="profile"><input id="profile_email" name="profile[email]" required></form>';
+            window.SvarohJsFormValidator.config = {};
+
+            window.SvarohJsFormValidator.addModel(buildModel('profile', 'profile', {
+                email: buildModel('profile_email', 'profile[email]'),
+            }), false);
+
+            // js_validator_config() of a template that prints it further down
+            window.SvarohJsFormValidator.config = { html5Validation: true };
+            document.dispatchEvent(new Event('DOMContentLoaded'));
+
+            expect(document.getElementById('profile').getAttribute('novalidate')).toBe('novalidate');
+        });
+    });
+
+    test('leaves no listener behind once the document is ready', () => {
+        withReadyState('loading', () => {
+            const callback = jest.fn();
+            window.SvarohJsFormValidator.onDocumentReady(callback);
+
+            document.dispatchEvent(new Event('DOMContentLoaded'));
+            document.dispatchEvent(new Event('DOMContentLoaded'));
+
+            expect(callback).toHaveBeenCalledTimes(1);
+        });
+    });
+
+    // A modal that fetches its form is opened again, a wizard step is
+    // revisited: the node of the previous render is gone from the document
+    test('forgets the instance of a render that was taken out of the document', () => {
+        const container = document.createElement('div');
+        document.body.appendChild(container);
+
+        const inject = () => {
+            container.innerHTML = '<form id="profile"><input id="profile_email" name="profile[email]"></form>';
+            window.SvarohJsFormValidator.addModel(buildModel('profile', 'profile', {
+                email: buildModel('profile_email', 'profile[email]'),
+            }));
+        };
+
+        inject();
+        inject();
+        inject();
+
+        const instances = window.SvarohJsFormValidator.getFormInstances('profile');
+        expect(instances).toHaveLength(1);
+        expect(instances[0].domNode).toBe(document.getElementById('profile'));
+        expect(window.SvarohJsFormValidator.forms.profile).toBe(instances[0]);
+    });
+
+    test('keeps every render that is still in the document', () => {
+        document.body.innerHTML = '<form id="profile"><input id="profile_email" name="profile[email]"></form>'
+            + '<form id="profile"><input id="profile_email" name="profile[email]"></form>';
+
+        window.SvarohJsFormValidator.addModel(buildModel('profile', 'profile', {
+            email: buildModel('profile_email', 'profile[email]'),
+        }));
+        window.SvarohJsFormValidator.addModel(buildModel('profile', 'profile', {
+            email: buildModel('profile_email', 'profile[email]'),
+        }));
+
+        const instances = window.SvarohJsFormValidator.getFormInstances('profile');
+        const rendered = document.querySelectorAll('[id="profile"]');
+        expect(instances).toHaveLength(2);
+        expect(instances[0].domNode).toBe(rendered[0]);
+        expect(instances[1].domNode).toBe(rendered[1]);
+    });
 });
 
 describe('SvarohJsFormValidator property paths', () => {