function imgChange(){
	i = Math.floor(Math.random() * 2);
	
	if(i == 0){
		document.getElementById("main1").innerHTML = "<img src='img/main_01.jpg' border='0'>"
	}else if(i == 1){
		document.getElementById("main1").innerHTML = "<img src='img/main_02.jpg' border='0'>"
	}
}