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

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.

encode it with JSON

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

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().

Micah's solution below worked for me as the site I had to customise was not in UTF-8, so I could not use json; I'd vote it up but my rep isn't high enough.

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

You can insert it into a hidden DIV, then assign the innerHTML of the DIV to your JavaScript variable. You don't have to worry about escaping anything. Just be sure not to put broken HTML in there.

You could try

<script type="text/javascript">
    myvar = unescape('<?=rawurlencode($myvar)?>');
</script>

htmlspecialchars

Description

string htmlspecialchars ( string $string [, int $quote_style [, string $charset [, bool $double_encode ]]] )

Certain characters have special significance in HTML, and should be represented by HTML entities if they are to preserve their meanings. This function returns a string with some of these conversions made; the translations made are those most useful for everyday web programming. If you require all HTML character entities to be translated, use htmlentities() instead.

This function is useful in preventing user-supplied text from containing HTML markup, such as in a message board or guest book application.

The translations performed are:

* '&' (ampersand) becomes '&'
* '"' (double quote) becomes '"' when ENT_NOQUOTES is not set.
* ''' (single quote) becomes ''' only when ENT_QUOTES is set.
* '<' (less than) becomes '&lt;'
* '>' (greater than) becomes '&gt;'

http://ca.php.net/htmlspecialchars

If you use a templating engine to construct your HTML then you can fill it with what ever you want!

Check out XTemplates. It's a nice, open source, lightweight, template engine.

Your HTML/JS there would look like this:

<script>
    var myvar = {$MyVarValue};
</script>