In this article, we will focus on the PHP highlight_string() function. We will provide you with an overview of the function, how it works, and examples of its use.

Introduction to the highlight_string() function

The highlight_string() function is a built-in function in PHP that is used to highlight the syntax of a string that contains PHP code. It can be used to display the syntax of a PHP string in a web page or to generate a formatted PHP string for documentation purposes.

The highlight_string() function takes a PHP string as its argument and generates an HTML representation of the string with syntax highlighting. It supports several configurable options to customize the output, such as specifying the CSS class for the highlighted syntax.

How to use the highlight_string() function

Using the highlight_string() function is very simple. You just need to call the function and pass the PHP string that you want to highlight. Here is an example:

$string = '<?php echo "Hello, World!"; ?>';

In this example, we have a variable $string that contains a PHP string that we want to highlight. We then call the highlight_string() function and pass the string as an argument. The function generates an HTML representation of the PHP string with syntax highlighting and outputs it to the browser.

Customizing the output

The highlight_string() function supports several options to customize the output. You can specify the CSS class for the highlighted syntax, the starting line number, and whether or not to use the short PHP tags <? instead of the standard tags <?php.

Here is an example of how to customize the output of the highlight_string() function:

$string = '<?php echo "Hello, World!"; ?>';
$options = array(
    'start_line' => 10,
    'css_class' => 'code',
    'use_short_tags' => true
highlight_string($string, true, $options);

In this example, we have a variable $options that contains an array of options for the highlight_string() function. We specify the starting line number as 10, the CSS class as code, and use short PHP tags. We then pass the options array as the third argument to the highlight_string() function.


In conclusion, the highlight_string() function is a powerful tool for generating formatted PHP strings with syntax highlighting. By understanding how to use the function and how to customize its output, you can take advantage of this feature to create more visually appealing and readable PHP code.

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