CSS/jQuery Circle

I need this done ASAP for my brother as I am busy working on another project. I need you to create a moving circle that moves randomly on the screen and reveals content "inside the circle" while outside the circle will be any background color I choose. The circle should move while the page is loading and hide once the page has fully loaded. Once the page is fully loaded the circle and mask clip will hide and all content will be visible. Your code should be very clean and cross-browser compatible.