Pass a PHP string to a JavaScript variable (and escape newlines) [duplicate]

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This question already has an answer here:

What is the easiest way to encode a PHP string for output to a JavaScript variable?

I have a PHP string which includes quotes and newlines. I need the contents of this string to be put into a JavaScript variable.

Normally, I would just construct my JavaScript in a PHP file, à la:

<script>
  var myvar = "<?php echo $myVarValue;?>";
</script>

However, this doesn’t work when $myVarValue contains quotes or newlines.

First answer

Expanding on someone else’s answer:

<script>
  var myvar = <?php echo json_encode($myVarValue); ?>;
</script>

Using json_encode() requires:

  • PHP 5.2.0 or greater
  • $myVarValue encoded as UTF-8 (or US-ASCII, of course)

Since UTF-8 supports full Unicode, it should be safe to convert on the fly.

Note that because json_encode escapes forward slashes, even a string that contains </script> will be escaped safely for printing with a script block.

Second answer

function escapeJavaScriptText($string)
{
    return str_replace("\n", '\n', str_replace('"', '\"', addcslashes(str_replace("\r", '', (string)$string), "
function escapeJavaScriptText($string)
{
    return str_replace("\n", '\n', str_replace('"', '\"', addcslashes(str_replace("\r", '', (string)$string), "\0..\37'\\")));
}
..'\"))); }

Third answer

I have had a similar issue and understand that the following is the best solution:

<script>
    var myvar = decodeURIComponent("<?php echo rawurlencode($myVarValue); ?>");
</script>

However, the link that micahwittman posted suggests that there are some minor encoding differences. PHP’s rawurlencode() function is supposed to comply with RFC 1738, while there appear to have been no such effort with Javascript’s decodeURIComponent().

Reprint:https://stackoverflow.com/questions/168214/pass-a-php-string-to-a-javascript-variable-and-escape-newlines
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