In our previous posts, we explored system files (sitemap.xml) and fine‑tuned SEO settings (Custom Robots Header Tags). Now, let’s move past the dashboard and dive into the engine room: the Theme Editor.
If you’ve ever looked at a Blogger theme’s HTML and wondered how it displays different elements on different pages—like showing a Related Posts section only on a single blog post, or a specific advertisement only on the homepage—the answer lies in Blogger’s Conditional Tags and Data Variables.
These built‑in tools are essential for achieving the kind of dynamic, customized user experience that sets professional blogs apart.
1️⃣ The Logic Gate: Blogger Conditional Tags
Conditional tags are the logic behind your theme. They are special XML‑based tags that act as IF/THEN statements, allowing you to execute a section of code only if a certain condition about the current page is met.
All conditional tags in Blogger follow the format: <b:if cond='data:condition'>...</b:if>.
🛠️ Essential Conditional Tags
| Condition | Code | Description |
|---|---|---|
| Homepage (Index) | data:blog.pageType == "index" |
Only displays on the main blog feed page. |
| Individual Post Pages | data:blog.pageType == "item" |
Only displays on single post pages. |
| Static Pages (e.g., About Us) | data:blog.pageType == "static_page" |
Only displays on standalone pages, not posts. |
| Search/Label Pages | data:blog.pageType == "archive" or data:blog.pageType == "label" |
Displays on date archives and label/tag index pages. |
🔗 Combining Conditional Tags
You can use basic logic operators to combine conditions:
- AND (
&&): Both conditions must be true. - OR (
||): At least one condition must be true. - NOT (
!=): The condition must be false.
<b:if cond='data:blog.pageType == "index" && data:blog.showMobileWidgets'>
<!-- Show widget only on homepage AND mobile -->
</b:if>
<b:if cond='data:blog.pageType == "item" || data:blog.pageType == "static_page"'>
<!-- Show widget on posts OR static pages -->
</b:if>
<b:if cond='data:blog.pageType != "index"'>
<!-- Show widget everywhere except homepage -->
</b:if>
2️⃣ Data Variables (Dynamic Content)
Data variables are placeholders that Blogger fills with dynamic information about the current blog, post, or layout element when the page is loaded. They allow you to display dynamic content like the post title, URL, or author name.
They are used in the format: <data:variable.name/>
⚙️ Essential Data Variables for Posts
| Variable | Code | What it Displays |
|---|---|---|
| Post Title | <data:post.title/> |
The title of the current post. |
| Post URL | <data:post.url/> |
The absolute permalink URL for the current post. |
| Post Snippet | <data:post.snippet/> |
A short summary or snippet of the post content. |
| Post Date (Formatted) | <data:post.dateHeader/> |
A formatted version of the post’s date header. |
💡 Practical Example: Conditional Advertising
A classic use of conditional tags is to show an advertisement only on post pages (where revenue is often highest) and only below the title’s closing tag, wrapped in a conditional:
<b:if cond='data:blog.pageType == "item"'>
<div class="post-ad-slot">
<!-- Your AdSense or other ad code goes here -->
</div>
</b:if>
This ensures ads appear only where they’re most effective, without cluttering other parts of your blog.
📚 Example Use Case
Imagine you want to display a “Related Posts” widget only on single post pages. By wrapping the widget code in <b:if cond='data:blog.pageType == "item"'>, you ensure it appears only where it’s relevant. Combine this with data variables like <data:post.title/> to dynamically pull in the current post title for personalization.
⚠️ Disclaimer
This tutorial is for educational purposes only. Blogger’s conditional logic and data variables may evolve over time. Always test changes in a safe environment before applying them to your live blog.
🌟 Final Thoughts
Conditional tags and data variables are the backbone of Blogger theme customization. By mastering these tools, you can create dynamic, professional layouts that respond intelligently to different page types. Whether you’re adding ads, widgets, or personalized content, these features give you full control over your blog’s presentation.