# 8. Richtext

A `richtext` type variable is used to represent and manipulate a sequence of characters that holds rich content.

```
<?
	var @rt: richtext
	@rt := "<strong>This text is very"
	@rt := @rt + ToRichText(" strong</strong>")
?>
```

#### Implicit HTML Encoding

When you concatenate a text value to a richtext variable, implicit encoding is applied to the text value. This is not always desired; therefore, the `ToRichText()` function can be used. Let’s dissect the example above.

```
var @rt: richtext
```

This line declares the variable `@rt` as `richtext`.

```
@rt := "<strong>This text is very"
```

Since the left-hand side `@rt` is of type `richtext` and the expression on the right-hand side is a literal text, the text is treated as richtext. The value of the variable `@rt` is now `<strong>This text is very`.

```
@rt := @rt + ToRichText(" strong</strong>")
```

Once again, the left-hand side `@rt` is of type `richtext`, but the expression on the right-hand side is a concatenation of `richtext` + `richtext`, resulting in the value `<strong>This text is very strong</strong>`.

What happens if we don't use the `ToRichText()` function?

```
@rt := @rt + " strong</strong>"
```

In this case, the expression is of `richtext` + `text`. When evaluating the right `text` operand, it will be coerced into `richtext`. During this conversion, the text value will be HTML encoded, resulting in `<strong>This text is very strong&lt;/strong&gt;`. This is not what we wanted in this example, as it generates malformed HTML.

So, be cautious when concatenating with `richtext`.

#### Postback

Fortunately, performing a postback with richtext is quite straightforward. You don't have to deal with localization, and updating the property with a new value is simply a matter of sending it back as is.

```html
<? register input @RichTextProperty ?>
<textarea name="<?attr OutputId(@RichTextProperty) ?>"><?= @RichTextProperty ?></textarea>
```

#### Print Output Overview

Since we are dealing with `richtext`, the encoding is mostly ignored, except for JavaScript encoding. Let’s assume we have a variable `var @rt: richtext` that holds the value `<p>I am a paragraph.</p>`. The following encoding (or lack thereof) will produce the corresponding outputs:

| Encoding        | Output                       |
| --------------- | ---------------------------- |
| `<?= @rt ?>`    | \<p>I am a paragraph.\</p>   |
| `<?attr @rt ?>` | \<p>I am a paragraph.\</p>   |
| `<?js @rt ?>`   | "\<p>I am a paragraph.\</p>" |
| `<?raw @rt ?>`  | \<p>I am a paragraph.\</p>   |