The PHP function htmlspecialchars() is important when exporting text to formats such as XML or HTML, where special characters have special meaning. This function replaces special characters with their corresponding HTML entities so that the characters are displayed as plain text and do not disrupt the document structure.

The use of htmlspecialchars() is especially important when displaying user input on a Web page to avoid potential security problems such as cross-site scripting (XSS).

For example, if we want to export the text "This is a & example " to XML, we need to use htmlspecialchars() with the argument ENT_XML1. This causes the special character "&" to be replaced with "&" to ensure valid XML.

Here is a brief example:

$input = "This is a & example";
$output = htmlspecialchars($input, ENT_XML1);
echo $output;
De uitvoer zal zijn: "This is a & example

Using htmlspecialchars() with ENT_XML1, special characters are correctly replaced with the appropriate XML entities, keeping your exported text data valid XML.