div {
width: 300px;
height: 100px;
background-color: pink;
border: 1px solid black;
}
#skewDiv {
/* IE 9 */
-ms-transform: skewY(20deg);
/* Opera */
-o-transform: skewY(20deg);
/* Mozilla */
-moz-transform: skewY(20deg);
/* Safari */
-webkit-transform: skewY(20deg);
/* Standard syntax */
transform: skewY(20deg);
}