What are common pitfalls to avoid when concatenating variables with strings in PHP, especially within HTML attributes?

When concatenating variables with strings in PHP, especially within HTML attributes, common pitfalls to avoid include forgetting to properly escape the variables to prevent XSS attacks, not properly handling special characters that may break the HTML structure, and not considering the context in which the concatenated string will be used. To solve this issue, always escape the variables using htmlspecialchars() function before concatenating them into HTML attributes. 

<?php
// Example variables
$name = "<script>alert('XSS attack');</script>";
$age = 25;

// Concatenating variables with strings in HTML attributes
echo '<input type="text" name="' . htmlspecialchars($name) . '" value="' . htmlspecialchars($age) . '">';
?>

Keywords

PHP concatenation variables strings HTML attributes

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