Why prototype.js stops all jquery to work?

Why prototype.js stops all jquery to work?

Hi.

I dont know why all jquery stops working when i add ‘prototype.js’ in header of my Magento store.

This is the website.
http://www.clients.fizmedia.com/indiafashion/

‘prototype.js’ called in line 24.

I have checked when i remove ‘prototype.js’ from header then all jquery working good but ‘Continue button on one page checkout stops working.

Please let me know what is the problem because ‘prototype.js’ is really need for one page checkout processing.

Hope i will get best answers.

Thanks.