What potential issues should I be aware of when formatting numbers in PHP for web display?

When formatting numbers in PHP for web display, one potential issue to be aware of is the use of different number formats in different locales. To ensure consistency in number formatting across different locales, you can use the `number_format()` function in PHP, which allows you to specify the number of decimal places, decimal point, and thousands separator.

// Format a number with two decimal places and commas as thousands separator
$number = 1234567.89;
$formatted_number = number_format($number, 2, '.', ',');
echo $formatted_number;