window.onload = newCard;
var usedNums = new Array(76);

function newCard() {
	if (document.getElementById) {
		for (var i=0; i<24; i++) {
			setSquare(i);
		}
	}
	else {
		alert("Sorry, your browser doesn't support this script");
	}
}

function setSquare(thisSquare) {
	var currSquare = "square" + thisSquare;
	var colPlace = new Array(0,1,2,3,4,0,1,2,3,4,0,1,3,4,0,1,2,3,4,0,1,2,3,4);
	var colBasis = colPlace[thisSquare] * 15;
	var newNum;

	do {
		newNum = colBasis + getNewNum() + 1;
	}
	while (usedNums[newNum]);

	usedNums[newNum] = true;
	document.getElementById(currSquare).innerHTML = newNum;
}

function getNewNum() {
	return Math.floor(Math.random() * 15);
}