Tab Order Checker
Fast, secure, client-side utility running entirely in your browser with zero server dependencies.
Tab Order Checker
Inspect DOM keyboard tab order sequence, detect positive tabindex antipatterns, and align visual layout with keyboard focus flow.
Tab Order Checker - Visual Focus Trajectory & Tabindex Inspector: Free Tab Order Checker tool: simulate sequential keyboard tab order through HTML interactive elements and detect broken DOM sequence, skipped controls.
How to Use the Tab Order Checker
Paste HTML Component Code
Insert any form, navigation menu, or complex page template containing inputs, links, buttons, and tabindex attributes.
Evaluate Actual Browser Focus Order
The tool calculates the exact sequence in which standard web browsers will tab through the elements (positive tabindex first, then natural DOM order).
Detect Positive Tabindex Antipatterns
Identifies elements using tabindex="1", "2", etc., which cause unpredictable cursor jumping and fail WCAG 2.4.3 Focus Order.
Align DOM Order with Visual Presentation
Review the step-by-step tab trajectory diagram and restructure HTML source order to match your visual CSS grid or flexbox design.
Comprehensive Guide: Tab Order Checker
WCAG Success Criterion 2.4.3 Focus Order requires that if a web page can be navigated sequentially and the navigation sequences affect meaning or operation, focusable components must receive focus in an order that preserves meaning and operability. For sighted keyboard navigators and screen reader users alike, an intuitive focus sequence must mirror the visual layout of the page from top-to-bottom and left-to-right.
Using positive tabindex attributes (`tabindex="1"`, `tabindex="2"`, etc.) is one of the most severe tab order antipatterns in web development. Browsers handle keyboard focus by first visiting all elements with a positive tabindex in numerical ascending order, completely ignoring their position in the HTML document. Only after exhausting every positive tabindex element does the browser return to the top of the page to visit standard native inputs and buttons. This creates jarring, disorienting jumps across the viewport.
Modern CSS layout engines (such as CSS Grid and Flexbox) introduce a subtle accessibility hazard: visual-source order mismatch. By utilizing CSS properties like `flex-direction: row-reverse`, `order: -1`, or arbitrary grid area positioning, a developer can display an element at the visual top of a screen while leaving it at the bottom of the HTML source code. Because keyboard focus strictly follows DOM order, tabbing through the page causes the cursor to jump erratically backwards across the screen.
The gold standard of accessible focus management is to keep all interactive elements in natural DOM source order and restrict `tabindex` strictly to two values: `tabindex="0"` (to introduce custom non-native components into the natural tab order) and `tabindex="-1"` (to enable programmatic script focusing without putting the element in keyboard tab flow).
Key Features & Capabilities
Visual Tab Sequence Flowchart
Calculates and displays the exact step-by-step keyboard tab stop progression across all interactive elements.
Positive Tabindex Flagging
Detects tabindex > 0 antipatterns that cause disorienting cursor jumps across the viewport.
WCAG 2.4.3 Conformance Assurance
Ensures logical reading and interaction sequence for sighted keyboard users and screen readers.
CSS Source Mismatch Prevention
Helps engineers align HTML DOM structure with CSS flexbox and grid visual layouts.
Programmatic Tabindex (-1) Tracking
Identifies elements reserved for JavaScript programmatic focus during modal and drawer activation.
100% Client-Side Evaluation
Audits code natively in your browser using DOMParser with zero network data transmission.
Frequently Asked Questions
Positive tabindex values (tabindex="1", "2", etc.) override natural reading order. When a user tabs onto a page, the browser jumps directly to the lowest positive number, bypassing all headers, menus, and previous form fields. As pages change or components update, maintaining positive tabindex numbers across an entire application becomes impossible and leads to broken focus navigation.
CSS visual reversal properties (such as row-reverse or flex-direction: column-reverse) reverse the visual layout on the screen, but DO NOT reverse the underlying DOM tab order. A keyboard user pressing Tab will move in the exact opposite direction of the visual layout, creating immense confusion.
Native HTML elements that automatically receive keyboard focus include: <a href>, <button>, <input> (except type="hidden"), <select>, <textarea>, and <details><summary>. Non-interactive elements like <div>, <p>, <span>, and <h1> are not focusable unless given a tabindex.
tabindex="-1" makes an element non-reachable via standard Tab key navigation, but allows JavaScript to programmatically move focus to it using element.focus(). This is standard best practice for error summaries after form submission, modal dialog container boxes, or notification toasts.
Yes. Sighted keyboard users rely on the Tab key to visit interactive controls, but screen reader users can navigate through every element (including headings, paragraphs, lists, and images) using dedicated screen reader reading keys (such as the Down Arrow or H key for headings).