Introduction:

In web development, HTML (Hypertext Markup Language) is the foundation of every webpage. It provides the structure and layout of the content displayed in a browser. Often, developers encounter scenarios where they need to convert plain text into HTML format dynamically. PHP, being a powerful server-side scripting language, offers several methods to accomplish this task. In this blog, we will explore multiple approaches to converting text to HTML using PHP.

Method 1: Using nl2br() Function

The first method we'll discuss involves using the nl2br() function in PHP. This function is specifically designed to insert HTML line breaks (<br>) before all newlines in a string, making it suitable for converting line breaks in plain text to their HTML equivalent.

<?php
$plainText = "Hello, world!\nThis is a new line.";
$htmlFormatted = nl2br($plainText);
echo $htmlFormatted;
?>

Output:

Hello, world!<br>This is a new line.

The nl2br() function scans the input string and replaces each newline (\n) with <br> tags, which, when rendered in a web browser, create line breaks.

Method 2: Using htmlspecialchars() Function

The htmlspecialchars() function is typically used to convert special characters to their HTML entities, but it can also help prevent code injection and ensure proper display of plain text as HTML.

<?php
$plainText = "Welcome to & openAI <script>alert('XSS attack');</script>";
$htmlFormatted = htmlspecialchars($plainText, ENT_QUOTES);
echo $htmlFormatted;
?>

Output:

Welcome to & openAI <script>alert('XSS attack');</script>

By using htmlspecialchars() with the ENT_QUOTES flag, we convert special characters like <, >, and & into their respective HTML entities. This way, potential HTML or script injections are neutralized, and the text is displayed as intended.

Method 3: Using strip_tags() Function

The strip_tags() function is another approach to converting text to HTML in PHP. However, it operates differently as it removes all HTML and PHP tags from the input text.

<?php
$plainText = "This is <b>bold</b> and <i>italic</i> text.";
$htmlFormatted = strip_tags($plainText);
echo $htmlFormatted;
?>

Output:

This is bold and italic text.

The strip_tags() function scans the text and removes any HTML or PHP tags present, leaving only the plain text content. This method is useful when you want to display text without any formatting.

Method 4: Using Regular Expressions

For more complex text-to-HTML conversions, regular expressions can be employed to match specific patterns and replace them with HTML tags.

<?php
$plainText = "Check out our website: www.example.com";
$htmlFormatted = preg_replace('/www\.[a-zA-Z0-9]+\.[a-zA-Z]{2,}/', '<a href="$0" target="_blank">$0</a>', $plainText);
echo $htmlFormatted;
?>

Output:

Check out our website: <a href="www.example.com" target="_blank">www.example.com</a>

Here, we use the preg_replace() function along with a regular expression to find occurrences of website URLs in the text and convert them into clickable links.

Method 5: Using Markdown

Markdown is a lightweight markup language that allows easy conversion of plain text to HTML. While PHP doesn't have a built-in Markdown parser, you can use third-party libraries like "Parsedown" or "PHP Markdown Extra" to achieve this.

<?php
require 'parsedown/Parsedown.php';
$plainText = "This is **bold** and _italic_ text.";
$parsedown = new Parsedown();
$htmlFormatted = $parsedown->text($plainText);
echo $htmlFormatted;
?>

Output:

<p>This is <strong>bold</strong> and <em>italic</em> text.</p>

In this method, we use the "Parsedown" library to convert Markdown-formatted text into HTML. It supports various formatting options like headers, lists, emphasis, etc., providing a versatile solution for text conversion.

Conclusion:

In this blog, we explored various methods to convert plain text to HTML using PHP. We started with the simple nl2br() function for adding line breaks and then moved on to htmlspecialchars() and strip_tags() functions for handling special characters and removing HTML tags, respectively. Additionally, we covered using regular expressions for pattern matching and replacement and using third-party libraries like "Parsedown" to process Markdown.