CSS
div:nth-child(1) { background-image: linear-gradient(to bottom, red, white); }
div:nth-child(2) { background-image: -ms-linear-gradient(top, red, yellow 25%, green 50%, blue 75%, purple); }
div:nth-child(3) { background-image: linear-gradient(30deg, red, yellow, white); }
div:nth-child(4) { background-image: -ms-linear-gradient(30deg, red, white); }
div:nth-child(5) { background-image: radial-gradient(at center, red, white); }
div:nth-child(6) { background-image: -webkit-radial-gradient(center, circle, red, white); }
div:nth-child(7) { background-image: radial-gradient(circle farthest-corner, red, white); }
div:nth-child(8) { background-image: -ms-radial-gradient(circle cover, red, white); }
div:nth-child(9) { background-image: radial-gradient(circle 50px at center, red, white); }
div:nth-child(10) { background-image: -ms-radial-gradient(center, 50px, 50px, red, white); }
div:nth-child(11) { background-image: radial-gradient(circle farthest-corner, red, white); }
div:nth-child(12) { background-image: -ms-radial-gradient(circle cover, red, white); }
div:nth-child(13) { background-image: -ms-radial-gradient(30px 40px, circle closest-side, red, white); }
div:nth-child(14) { background-image: -ms-radial-gradient(30px 40px, circle closest-corner, red, white); }
div:nth-child(15) { background-image: -ms-radial-gradient(30px 40px, circle farthest-side, red, white); }
div:nth-child(16) { background-image: -ms-radial-gradient(30px 40px, circle farthest-corner, red, white); }
div:nth-child(17) { background-image: radial-gradient(30px 40px at 40px 40px, red, white); }
div:nth-child(18) { background-image: radial-gradient(red, white); }