How Can I Reliably Remove Multiple UTF-8 BOM Sequences from PHP Template Files?

Eliminating Multiple UTF-8 BOM Sequences

In response to the issue of outputting raw HTML from template files using PHP5, where the removal of the Byte Order Mark (BOM) was not resolving Firefox compatibility, a more comprehensive solution has been identified.

When attempting to remove the BOM, the code provided:

if (substr($t, 0, 3) == b'\xef\xbb\xbf') {
    $t = substr($t, 3);
}

only addresses the removal of a single BOM sequence. However, to ensure compatibility with Firefox, it is necessary to eliminate all instances of the BOM.

Revised Code for BOM Removal

To remove multiple UTF-8 BOM sequences, the following code is recommended:

function remove_utf8_bom($text)
{
    $bom = pack('H*','EFBBBF');
    $text = preg_replace("/^$bom/", '', $text);
    return $text;
}

Explanation of the Code

• pack('H*','EFBBBF'): This line creates a binary string representation of the UTF-8 BOM.
• preg_replace("/^$bom/", '', $text): This line uses regular expressions to search for and remove all occurrences of the BOM sequence at the beginning of the string (^ denotes the beginning of the string).

By implementing this code, the template files will be rendered correctly, resolving the compatibility issue with Firefox.

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