How Can I Safely Transfer PHP Variables to JavaScript?

Transferring PHP Variables to JavaScript

Encoding PHP strings for use in JavaScript can present difficulties when the string contains characters like quotes and newlines. The recommended solution involves utilizing PHP's json_encode() function to convert the string into JSON format:

<script>
  var myvar = <?= json_encode($myVarValue, JSON_UNESCAPED_UNICODE); ?>;
</script>

To ensure compatibility, this method requires:

• PHP version 5.2.0 or higher
• The PHP string must be encoded in UTF-8

Since UTF-8 encompasses full Unicode, this solution allows for secure conversion on the fly.

It's important to note that when using this method in HTML attributes such as onclick, it's necessary to apply the htmlspecialchars() function to the json_encode() output. This prevents potential issues with characters like &bar; being misinterpreted as HTML entities in strings like foo()& and &bar;.

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