//flag

ch=1;

//イメージ切り替え

function changeimg(cx,urlimg){
		var cont1=document.getElementById("txt_box01");
		var cont2=document.getElementById("txt_box02");
		var cont3=document.getElementById("txt_box03");
		var cont4=document.getElementById("txt_box04");
		
		switch(cx){
			case 1:
				document.mainphotoimg.src=urlimg;
				cont1.style.display="block";
				cont2.style.display="none";
				cont3.style.display="none";
				cont4.style.display="none";
				ch=1;
				break;
				
			case 2:
				document.mainphotoimg.src=urlimg;
				cont1.style.display="none";
				cont2.style.display="block";
				cont3.style.display="none";
				cont4.style.display="none";
				ch=2;
				break;
			case 3:
				document.mainphotoimg.src=urlimg;
				cont1.style.display="none";
				cont2.style.display="none";
				cont3.style.display="block";
				cont4.style.display="none";
				ch=3;
				break;
			case 4:
				document.mainphotoimg.src=urlimg;
				cont1.style.display="none";
				cont2.style.display="none";
				cont3.style.display="none";
				cont4.style.display="block";
				ch=4;
				break;
		}
}