Alternate colors every <input type="text" id="everyHowmany" size="1" value="3" onkeyup="updateList();" /> rows, using
<select id="numOfColors" onmouseup="updateList();" onkeyup="updateList();" onblur="updateList();" onchange="updateList();">
	<option>1</option>
	<option>2</option>
	<option selected>3</option>
	<option>4</option>
	<option>5</option>
</select> different colors. (I would have liked to add a feature to alternate spacing, but CSS <a href="javascript: alert('MSN\nLuc says (2:45 [in the morning]):\noh great, now i get why it won\'t work.\npadding-top: -10px; doesn\'t do anything\nmargin-top: -10px; works fine\nmargin-top: 10px; leaves uncolored gaps\npadding-top: 10px; works fine\nDarnit. I\'m not going to add an alternation between padding and margin anymore now.\n\nSome background: I\'ve spent about 1h30mins searching for a good formula for the alternating colors thing, I\'ve found none and came up with the current solution. That is quite annoying already. Then this problem...');">sucks too hard</a>.)
<br />
<br />
<div id="list"></div>
<script type='text/javascript'>
	var words = ["Adult", "Aeroplane", "Aircraft Carrier", "Airforce", "Airport", "Album", "Alphabet", "Apple", "Army", "Baby", "Baby", "Backpack", "Balloon", "Banana", "Bank", "Barbecue", "Bathroom", "Bathtub", "Bible", "Bird", "Bomb", "Book", "Boss", "Bottle", "Bowl", "Brain", "Bridge", "Butterfly", "Button", "Cappuccino", "Car-race", "Carpet", "Carrot", "Cave", "Chair", "Chess Board", "Chief", "Child", "Chisel", "Chocolates", "Church", "Church", "Circle", "Circus", "Circus", "Clock", "Clown", "Coffee", "Coffee-shop", "Comet", "Compact Disc", "Compass", "Computer", "Crystal", "Cup", "Cycle", "Data Base", "Desk", "Diamond", "Dress", "Drill", "Drink", "Drum", "Dung", "Ears", "Earth", "Electricity", "Elephant", "Eraser", "Explosive", "Eyes", "Family", "Feather", "Festival", "Film", "Finger", "Fire", "Floodlight", "Flower", "Foot", "Fork", "Freeway", "Fruit", "Fungus", "Game", "Garden", "Gate", "Gemstone", "Girl", "Gloves", "Grapes", "Guitar", "Hammer", "Hieroglyph", "Highway", "Horoscope", "Horse", "Hose", "Ice", "Ice-cream", "Insect", "Jet fighter", "Junk", "Kaleidoscope", "Kitchen", "Knife", "Library", "Liquid", "Magnet", "Maze", "Meat", "Meteor", "Microscope", "Milk", "Milkshake", "Mist", "Money", "Monster", "Mosquito", "Mouth", "Nail", "Navy", "Necklace", "Needle", "Onion", "PaintBrush", "Pants", "Parachute", "Passport", "Pebble", "Pendulum", "Pepper", "Perfume", "Pillow", "Plane", "Planet", "Pocket", "Post-office", "Potato", "Printer", "Prison", "Pyramid", "Radar", "Rainbow", "Record", "Restaurant", "Rifle", "Ring", "Robot", "Rock", "Rocket", "Roof", "Room", "Rope", "Saddle", "Salt", "Sandpaper", "Sandwich", "Satellite", "School", "Ship", "Shoes", "Shop", "Shower", "Signature", "Skeleton", "Slave", "Snail", "Software", "Solid", "Space Shuttle", "Spectrum", "Sphere", "Spice", "Spiral", "Spoon", "Sports-car", "Spot Light", "Square", "Staircase", "Star", "Stomach", "Sunglasses", "Surveyor", "Swimming Pool", "Sword", "Table", "Tapestry", "Teeth", "Telescope", "Television", "Tennis racquet", "Thermometer", "Tiger", "Toilet", "Tongue", "Torch", "Torpedo", "Train", "Treadmill", "Triangle", "Tunnel", "Typewriter", "Umbrella", "Vacuum", "Vampire", "Videotape", "Vulture", "Water", "Weapon", "Web", "Wheelchair", "Window", "Woman", "Worm", "X-Ray"];
	function getById(id) {
		return document.getElementById(id);
	}
	
	function even(n) { //2 = 0, 3 = 1. Checks whether a number is even.
		return n % 2 == 0 ? 0 : 1;
	}
	
	function updateList() {
		if (getById("everyHowmany").value == "" || isNaN(getById("everyHowmany").value))
			return;
		
		var str = "<table>";
		switch(parseInt(getById("numOfColors").value)) {
			case 1:
				var cols = ["F"];
				break;
			case 2:
				var cols = ["F", "A"];
				break;
			case 3:
				var cols = ["F", "C", "A", "C"];
				break;
			case 4:
				var cols = ["F", "D", "B", "A", "C", "E"];
				break;
			case 5:
				var cols = ["F", "E", "C", "B", "A", "B", "C", "D", "E"];
				break;
		}
		for (var i = 0; i <= 500; i++) {
			var everyHowmany = parseInt(getById("everyHowmany").value);
			str += "<div style='background-color: #" + Array(4).join(cols[Math.floor(i / everyHowmany) % cols.length]) + ";'>"
				+ "<div style='text-align:left;height:0px;'>"
					+ words[Math.round(Math.random() * words.length)]
				+ "</div>"
				+ "<div style='text-align:right;'>"
					+ words[Math.round(Math.random() * words.length)]
				+ "</div>"
			+ "</div>";
		}
		str += "</table>";
		getById("list").innerHTML = str;
	}
	
	updateList();
</script>