[javascript] WordPress path url in js script file

According to the Wordpress documentation, you should use wp_localize_script() in your functions.php file. This will create a Javascript Object in the header, which will be available to your scripts at runtime.

See Codex

Example:

<?php wp_localize_script('mylib', 'WPURLS', array( 'siteurl' => get_option('siteurl') )); ?>

To access this variable within in Javascript, you would simply do:

<script type="text/javascript">
    var url = WPURLS.siteurl;
</script>