Differences in Using nl2br and nl2br() Functions with Different Parameters

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<p>Differences in Using nl2br and nl2br() Functions with Different Parameters</p>
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<p>In PHP, the nl2br() function converts newline characters (\n or \r\n) in a string into HTML <br> tags.</p>
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<p>This is commonly used when displaying text input from users, such as multi-line form submissions.</p>
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<p>Function signature:</p>
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<p>string nl2br(string $string, bool $is_xhtml = true)</p>
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<p>Parameter explanation:</p>
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<p>$string: The string to process.</p>
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<p>$is_xhtml: Optional, defaults to true.</p>
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<p>true generates XHTML-style <br /> tags.</p>
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<p>false generates standard HTML <br> tags.</p>
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<p>Use case analysis:<br>
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<p>// Scenario 1: Displaying plain text while keeping HTML compatibility<br>
$text1 = "First line\nSecond line\nThird line";<br>
echo nl2br($text1); // Outputs text with <br /> suitable for XHTML pages</p>
<p>// Scenario 2: Non-XHTML page, generate standard HTML tags<br>
$text2 = "Hello\nWorld";<br>
echo nl2br($text2, false); // Outputs text with <br> tags suitable for standard HTML pages</p>
<p>// Scenario 3: Output after database storage, ensuring visible line breaks<br>
$textFromDb = "User input text\nwith line breaks";<br>
echo nl2br($textFromDb); // Defaults to <br />, displaying line breaks on the webpage</p>
<p>// Scenario 4: Output with HTML tags, avoiding HTML parsing errors<br>
$textHtml = "This is <b>bold</b>\nline break test";<br>
echo nl2br($textHtml, true); // Automatically converts line breaks without breaking HTML structure</p>
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<p>Summary:</p>
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<p>The main function of nl2br() is to convert newline characters into HTML-recognizable <br> tags.</p>
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<p>The $is_xhtml parameter determines whether the generated line break tags comply with XHTML standards.</p>
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<p>For XHTML pages or situations requiring strict tag closure, use the default true.</p>
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<p>For standard HTML pages or for compatibility with older browsers, set to false.</p>
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<p>nl2br() is commonly used to display user input, log text, or multi-line string content.<br>
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