jpgArray = new Array(
'square1.gif',
'square2.gif',
'square3.gif',
'square4.gif',
'square5.gif',
'square6.gif',
'square7.gif',
'square8.gif',
'square9.gif',
'square10.gif',
'square11.gif',
'square12.gif',
'square13.gif',
'square14.gif',
'square15.gif',
'square16.gif',
'square17.gif',
'square18.gif');

var usedImgs = '';


function randNum (num) {
	//var now = new Date();
	var rand = Math.round((num-1) * Math.random());  
	if (usedImgs.indexOf("|" + rand.toString() + "|") != -1)  return randNum(num);
	usedImgs += "|" + rand.toString() + "|";
	if (jpgArray[rand] == "") alert(rand);
	return rand;
}


function randPics(){

	s1 = document.getElementById('sq1');
	s2 = document.getElementById('sq2');
	s3 = document.getElementById('sq3');
	s4 = document.getElementById('sq4');
	
	s1.src = 'images/' + jpgArray[randNum(jpgArray.length)];
	s2.src = 'images/' + jpgArray[randNum(jpgArray.length)];
	s3.src = 'images/' + jpgArray[randNum(jpgArray.length)];
	s4.src = 'images/' + jpgArray[randNum(jpgArray.length)];
}