3 <body style=
"background-color: green; overflow:hidden">
4 <div style=
"position:fixed; left: 0px; top: 0px; width: 100px; height: 500px; background-color: purple; z-index: -1"></div>
5 <div style=
"position:fixed; left: 10px; top: 10px; width: 10px; height: 10px; background-color: blue"></div>