During a recent session of browsing Facebook and utilizing the Firebug network debugger, I made an interesting observation regarding the AJAX responses generated by Facebook. I noticed that all of these responses begin with an empty for loop structure.
For example:
for(;;);{...}
I am curious to understand the purpose behind this practice. My assumption is that it serves as a security measure against XSS attacks, but I would appreciate further clarification on this matter. Thank you!