window.onload = choosePic; 

var myPix = new Array("i/rndHeadImg/giris01.jpg", "i/rndHeadImg/giris02.jpg", "i/rndHeadImg/giris03.jpg", "i/rndHeadImg/giris04.jpg", "i/rndHeadImg/giris05.jpg", "i/rndHeadImg/giris06.jpg", "i/rndHeadImg/giris07.jpg", "i/rndHeadImg/giris08.jpg", "i/rndHeadImg/giris09.jpg", "i/rndHeadImg/giris10.jpg", "i/rndHeadImg/giris11.jpg");

function choosePic()
{
	randomNum = Math.floor((Math.random() * myPix.length));
	document.getElementById("girisImg").src = myPix[randomNum];
}