How can the use of eval() function in PHP code impact the display of content and potentially lead to errors like scripts not showing up as expected?

Using the eval() function in PHP code can impact the display of content and potentially lead to errors because it allows for the execution of arbitrary PHP code stored in a string. This can make the code harder to read and maintain, as well as introduce security vulnerabilities if the input is not properly sanitized. To avoid these issues, it's recommended to refactor the code to avoid using eval() wherever possible.

// Avoid using eval() by refactoring the code
$var = 'Hello, World!';
echo $var;