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encoding a PHP variable with quotes and line breaks to be passed to a Javascript function (and then reverse the encoding)

Answer 1

+1 A:

You can use json_encode if available. It encodes the string according to the JSON data format that is a subset of JavaScript; so any JSON is also valid JavaScript.

<script type="text/javascript">
<?php
    echo 'alert('. json_encode($str).');';
?>
</script>

Otherwise try PHP’s rawurlencode and decode it with JavaScript’s decodeURI:

<script type="text/javascript">
<?php
    echo 'alert(decodeURI("'. rawurlencode($str).'"));';
?>
</script>

Gumbo 2010-07-13 18:35:10

Thanks, just to follow up, decodeURI almost works, but doesn't decode certain characters like /, so I went with decodeURIComponent, as you can see in my answer...

bobbyh 2010-07-14 19:31:33

Answer 2

+2 A:

simplest would be to use json_encode()

Scott Evernden 2010-07-13 18:36:24

Answer 3

A:

Json is the solution. See sample code Two pages to demonstrate

First Page json.php

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;
<html xmlns="http://www.w3.org/1999/xhtml"&gt;
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Untitled Document</title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"&gt;&lt;/script&gt;
</head>

<body>


<script type="text/javascript">
  $(document).ready(function() {
    // This is more like it!
    $('#submit').live('click', function() {
        var id=$("#id").attr("value");
        $.getJSON("json-call.php", {id:id}, function callback(data) {
            $("#list").html("var1:"+data['var1']+"<br/>"+"var2:"+data['var2']+"<br />id:"+data['id']);
        });
    });

  });
</script>

<input id="id" type="text" value="test value" />
<input type="button" id="submit" value="submit" />

<div id="list"></div>


</body>
</html>

Second Page json-call.php

$var1 = 'your name';
$var2 = 'your address';
$id = $_REQUEST['id'];
print(json_encode(array ('var1' => $var1, 'var2' => $var2, 'id'=>$id)));

and Results

var1:your name
var2:your address
id:test value

Ghost 2010-07-13 19:53:33

Answer 4

A:

Not sure whether json_decode does everything you need. htmlspecialchars() and htmlspecialchars_decode() should do the trick for everything but the line breaks. The line breaks are kind of a pain, since the combination of linebreaks and carriage returns will depend on the browser, but I think something like this should work:

$value = "your string with quotes and newlines in it.";

//take cares of quotes
$js_value = htmlspecialchars($value);    
//first line replaces an ASCII newline with a JavaScript newline
$js_value = str_replace("\n",'\n',$js_value);
//second line replaces an ASCII carriage return with nothing, so you don't get duplicates
$js_value = str_replace("\r",'',$js_value);

//reverse to convert it back to PHP
$php_value = str_replace('\n',"\r\n",$js_value);  
$php_value = htmlspecialchars_decode($php_value);

Maybe not the most elegant solution, but that's not really my specialty. ;) Also, keep in mind that newline characters will just end up like spaces in an <input type="text"> field.

NChase 2010-07-13 20:23:56

Answer 5

A:

Here is a litle something I have made:

function safefor_js($str) {
    return str_replace(array("'",'"',"\n"), array('\x22','\x27','\\n'), $str);
}

Echo 2010-07-13 20:25:39

What about the backslash character?

Gumbo 2010-07-13 20:56:42

I didn't think of that, but I don't think it is needed. I just tested it with things like: "a\na", "a\x22a", "a\xn\x22a", "a\x27a" (all with out the quotes) and it did not break the page in any way. Is there something I'm missing? If I'm wrong I definitely would want to fix it.

Echo 2010-07-13 21:08:28

Answer 6

+1 A:

I ran into problems using some of the answers proposed here, including issues with line breaks and decoding certain html entitites like /. I ended up using rawurlencode (in PHP) and decodeURIComponent (in Javascript) as matching functions to encode/decode the string so it could be passed as a JS variable. Here is working code for anybody else running into this problem.

<?php
$str =<<<EOT
Tromp L'oeil Sheath Dress

You will certainly "trick the eye" of many in this gorgeous illusion. Add it to your fall wardrobe before it disappears.
Available in Black/Nude
EOT;
echo 'here is the string: <pre>' . $str . '</pre>';
?>
<p>below is the variable doc.write'd after being rawurlencod'ed in PHP then decodeURIComponent'ed in JS:</p>
<script type="text/javascript">
<?php
echo 'document.write(decodeURIComponent("'. rawurlencode($str).'"));';
?>

bobbyh 2010-07-13 22:13:50

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encoding a PHP variable with quotes and line breaks to be passed to a Javascript function (and then reverse the encoding)

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