# Using server-side includes

> Turn on Server-Side Includes with .shtml files or .htaccess to reuse headers and footers and add simple dynamic content.

Source: https://helpcenter.ruachost.com/developers/web-servers/using-server-side-includes/

**Server‑Side Includes (SSI)** allow you to embed dynamic content into your web pages. On **ruachost.com**, SSI is supported on Apache servers and can be enabled through `.htaccess` directives or by using `.shtml` files.

## Why Use SSI?

- Reuse common HTML code (headers, footers, menus).
- Display dynamic information (last modified date, environment variables).
- Add conditional logic to web pages.
- Simplify site maintenance by centralizing shared content.

## Enabling SSI

### Method 1: Use `.shtml` Files

- By default, SSI is enabled for files ending in `.shtml`.
- Rename your HTML file to `.shtml` and insert SSI directives.

### Method 2: Enable SSI for `.html` or `.htm` Files

Add the following to your `.htaccess` file:

```
Options +Includes
AddType text/html .html
AddOutputFilter INCLUDES .html
AddType text/html .htm
AddOutputFilter INCLUDES .htm
```

## Common SSI Directives

### 1. Display Last Modified Date

```
<p><em>Page last modified on <!--#echo var="LAST_MODIFIED" --></em></p>
```

### 2. Reuse HTML Code (e.g., Footer)

```
<!--#include virtual="footer.html" -->
```

### 3. Conditional Expressions

```
<!--#if expr="$DATE_LOCAL = /^Saturday/ || $DATE_LOCAL = /^Sunday/" -->
<p>It's the weekend!</p>
<!--#else -->
<p>It's not the weekend...</p>
<!--#endif -->
```

> **Important Notes:**
- SSI directives begin with `<!--#` and end with `-->`.
- Ensure your server has **mod_include** enabled (Ruachost servers support this).
- SSI is processed on the server, unlike JavaScript which runs on the client.
- Overuse of SSI can affect performance; use for lightweight tasks.