As i remember when we do the dynamic webpage with php, the address of the page is usually look like this
but now when i see webpages that are written in php (At least part of it) they have address look like this:
which req is variable and should have value like bar=foo
The good example is facebook.com which when you try to upload your image the address is look like this
I just want to know dose anybody know what is behind those kind of urls?