How Front-End Developers Can Check and Implement On-Page SEO

SEO (Search Engine Optimization) is the practice of improving a website's ranking in search engine results by following the engines' rules, helping businesses gain visibility and traffic.

Because the internet is ubiquitous, SEO has become an essential channel for companies to promote themselves, reaching users regardless of location, industry, or background.

How front‑end developers can check on‑page SEO: Open Chrome DevTools (F12) and run the Audits/Lighthouse tool. The report highlights errors and suggestions for fixing on‑page issues.

Writing effective title, description, and keywords:

Title should follow the pattern "SiteName – Primary Keyword or Descriptive Phrase"; place the most important words at the beginning. Example:

<title>SEO_站内SEO-网站SEO</title>
<meta name="Description" Content="前端SEO-网站SEO-站内SEO">
<meta name="Keywords" Content="SEO,为什么要做-SEO,SEO-如何做">

Descriptions combine the page title, key content, and keywords into a concise summary. Keywords should reflect the page's main topics, be limited to three, and be separated by hyphens.

Semantic HTML recommendations: Minimize use of non‑semantic div and span tags, avoid presentational tags like b , font , u , and use CSS for styling. When using tables, employ caption , thead , tbody , tfoot , th , and td appropriately.

Example of a semantic HTML layout:

<div class="box1">
    <header> header</header>
    <nav> nav </nav>
    <section>
        <main>
            <article>
                <header> article header</header>
                <section style="width:100%;height:208px;background:#555555;"> section </section>
                <footer> article footer</footer>
            </article>
        </main>
        <aside>
            <h4> aside</h4>
        </aside>
    </section>
    <footer> footer </footer>
    <img alt="SEO优化指南图" src="../seo.png">
</div>

Corresponding CSS (kept unchanged):

.box1{width:500px;height:537px;margin:20px auto;text-align:center;font-size:20px;}
header{width:500px;height:45px;background:#888888;margin-bottom:10px;}
footer{width:500px;height:45px;background:#888888;margin-top:5px;}
section{width:500px;height:360px;}
nav{width:500px;height:45px;float:left;background:#888888;margin-bottom:5px;}
main{width:300px;height:300px;float:left;}
article{width:301;height:180px;background:#888888;margin-top:5px;}
article header{width:300px;height:31px;margin:10px 0 10px;}
article footer{width:300px;height:31px;margin:10px 0 10px;}
aside{width:195px;height:290px;float:right;background:#888888;margin-left:5px;margin-top:10px;}

Non‑decorative images must include an alt attribute: The alt text provides a textual alternative when the image cannot be displayed and helps search engines understand the image content.

<img alt="SEO优化指南图" src="../seo.png">

Using descriptive alt text can improve content relevance and keyword density, especially for banner images that dominate the homepage.

Internal vs. external SEO: Front‑end developers focus on internal (on‑page) SEO, ensuring search engines can crawl and understand the page structure. External SEO involves content promotion and link building, often handled by marketers, and complements internal efforts.