WordPress functions inside javascript

Hi, i’m currently developing a simple template for wordpress but i ran into a little problem.

Into the my template folder i have another folder called “lib” inside there is a file called jquery.ufvalidator.js, this file handles the form validation.

This is a part of the code

$.formValidator.defaults = {
		reqMailNotValid	:	'<img src="images/error.png" alt="img"/>',
		reqMailEmpty	:	'<img src="images/error.png" alt="img"/>',

of course now the template can not recall the image in the images folder, how can i point the javascript to the right folder ? I tried to write <?php bloginfo('template_url'); ?>/ but it did not work…

how can i fix this problem ?