I had this same problem a week ago.
First of all I noticed your URL has an ampersand preceding the parameter string, but it probably needs to have a question mark instead to begin the parameter string, followed by an ampersand between each additional parameter.
Now, you do need to escape your URL but also double-escape the URL parameters (title or other content you need to provide content in the Share) you are passing to the URL, as follows:
var myParams = 't=' + escape('Some title here.') + '&id=' + escape('some content ID or any other value I want to load');
var fooBar = 'http://www.facebook.com/share.php?u=' + escape('http://foobar.com/superDuperSharingPage.php?' + myParams);
Now, you need to create the above-linked superDuperSharingPage.php, which should provide the dynamic title, description, and image content you desire. Something like this should suffice:
<?php echo $title;?>
Let me know if this works for you, it's essentially what did for me :)
