PHP get_html_translation_table() Function

What You’ll Learn

The get_html_translation_table() function returns the character → HTML entity map that powers htmlspecialchars() and htmlentities(). Inspect it to understand encoding, or pass it to strtr() for manual or customized escaping.

Definition and Usage

In PHP, get_html_translation_table() exposes the lookup array behind HTML encoding functions. Each key is a single character (such as < or &); each value is the entity string PHP would substitute (such as < or &).

📝 Syntax

The function accepts a table type, optional flags, and encoding:

array get_html_translation_table(
    int $table = HTML_SPECIALCHARS,
    int $flags = ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401,
    string $encoding = "UTF-8"
)

Parameters

• $table — HTML_SPECIALCHARS (small set: &, <, >, quotes) or HTML_ENTITIES (full entity set used by htmlentities()).
• $flags — bitmask controlling quotes and document type. Common values: ENT_COMPAT, ENT_QUOTES, ENT_NOQUOTES, ENT_HTML401, ENT_HTML5.
• $encoding — character encoding (default UTF-8).

Return Value

Returns an associative array: original characters as keys, HTML entity strings as values.

Examples Gallery

Run these examples in PHP 7+. Each demonstrates a common pattern beginners encounter with get_html_translation_table().

<?php
$table = get_html_translation_table(HTML_SPECIALCHARS, ENT_COMPAT);

foreach ($table as $char => $entity) {
    echo json_encode($char) . " => $entity\n";
}
?>

"&" => &
"<" => &lt;
">" => &gt;
""" => &quot;

<?php
$compat  = get_html_translation_table(HTML_SPECIALCHARS, ENT_COMPAT);
$quotes  = get_html_translation_table(HTML_SPECIALCHARS, ENT_QUOTES);

echo "ENT_COMPAT entries:  " . count($compat) . "\n";
echo "ENT_QUOTES entries:  " . count($quotes) . "\n";
echo "Has apostrophe map:  " . (isset($quotes["'"]) ? "yes\n" : "no\n");
?>

ENT_COMPAT entries:  4
ENT_QUOTES entries:  5
Has apostrophe map:  yes

<?php
$special = get_html_translation_table(HTML_SPECIALCHARS, ENT_QUOTES);
$full    = get_html_translation_table(HTML_ENTITIES, ENT_QUOTES);

echo "HTML_SPECIALCHARS: " . count($special) . " entries\n";
echo "HTML_ENTITIES:     " . count($full) . " entries\n";

// Sample from full table
echo "Copyright sign: " . ($full["©"] ?? "n/a") . "\n";
?>

HTML_SPECIALCHARS: 5 entries
HTML_ENTITIES:     250+ entries
Copyright sign: ©

<?php
$text  = 'Tom & Jerry <script>alert("x")</script>';
$flags = ENT_QUOTES;

$table  = get_html_translation_table(HTML_SPECIALCHARS, $flags);
$manual = strtr($text, $table);
$built  = htmlspecialchars($text, $flags);

echo "Manual (strtr):     $manual\n";
echo "htmlspecialchars:   $built\n";
echo "Match:              " . ($manual === $built ? "yes\n" : "no\n");
?>

Manual (strtr):     Tom & Jerry <script>alert("x")</script>
htmlspecialchars:   Tom & Jerry <script>alert("x")</script>
Match:              yes

<?php
// Build once — reuse for many strings
$table = get_html_translation_table(HTML_SPECIALCHARS, ENT_QUOTES);
$table["…"] = "&hellip;";  // custom: ellipsis
$table["—"] = "&mdash;";   // custom: em dash

$inputs = [
    "Wait… what?",
    "Range: 1—10",
    "Plain & simple",
];

foreach ($inputs as $line) {
    echo strtr($line, $table) . "\n";
}
?>

Wait… what?
Range: 1—10
Plain & simple

🚀 Common Use Cases

• Debugging encoding — inspect which characters PHP converts and to which entities.
• Custom sanitization — merge extra mappings before strtr().
• Batch processing — build the table once, reuse for thousands of strings.
• Learning htmlspecialchars() — see the exact map behind the function.
• Word/document cleanup — extend the table for smart quotes and dashes from pasted text.

📝 Notes

• Only two valid $table values: HTML_SPECIALCHARS and HTML_ENTITIES (not HTML_QUOTE_SINGLE or similar).
• Default flags changed in PHP 8.1 to ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401.
• Call once and reuse—building the table inside a loop is noticeably slow.
• Entity forms match htmlspecialchars() / htmlentities() only—not every possible HTML encoding variant.
• For normal page output, prefer htmlspecialchars($text, ENT_QUOTES, 'UTF-8') directly.

💡 Best Practices