magento escape string for javascript - php

Question

Is there a helper function that will properly escape a string to be rendered as a single quote quoted JavaScript string literal?
I know of jsQuoteEscape but it only handles quotes and does not treat \n & \r etc.
so if my string is 'line1\nlineb' (i.e. two lines with a newline between them)
and I use
var jsvar='<?php echo $this->helper('myextension')->jsQuoteEscape($mystring); ?>';
I will get in the rendered content
var jsvar='line1
line2';
which is a syntax error.
Thanks,
Eyal

Answer 1

Yes
$string = 'Hello
There';
var_dump( Mage::helper('core')->jsonEncode($string) );
var_dump( json_encode($string) );
I've never been clear if this encoding a non-object string datatypes as a javascript string is a side-effect of the JSON encoding, or if it's true, according to Hoyle Crockford JSON, so I always like to wrap my strings in an object when passing them around
$o = new stdClass();
$o->param = 'This is my
Param';
$json = json_encode($o);
echo 'var data = ' . $json . ';' . "\n";
echo 'var jsdata = data.param';
This is how you'd handle this with javascript. There's no method that's build specifically for this. If you're interested in seeing the helper methods you do have available from a block, checkout the methods in
app/code/core/Mage/Core/Block/Abstract.php
app/code/core/Mage/Core/Block/Template.php
and if you're dealing with a template that's part of a block higher up the chain, get its class and then check its definition
var_dump get_class($this);