How to not wait to load a page while another one is not loaded

Question

Hi,

there is two files on a site.

domain.com/1.asp domain.com/2.asp

1.asp takes at least 5 minutes to load (because it does too much thing) while 1.asp is doing its job, i try to open 2.asp (it monitors how 1.asp is going) but 2.asp doesnt load unless 1.asp is loaded.

so how can i connect multiple files on a site

i think this is about IIS but i couldn't figure out.

thank you