how can make one page depend on other page

[aayatoos]

how can make second page display only if they only go throw the first page
for example :
if the user now the url of the second page and he put it, it display for him the first page immediately

thanks

[crosbystillsnas]

register a session variable on page1 and check for it on page2.
if it doesnt exist on page2 you can redirect to page1.