function imgshow() {
var j = 1;
var Img = document.getElementsByTagName("img");

for (var i = 0; i < Img.length; i++) {	
	if (Img[i].className == 'imgchair') {
		if ( j == 4 ) { j = 1; }
		Img[i].setAttribute("src", 'images/img'+j+'.jpg'); 
		j++;
	}
	}
}

function imgshow2() {
var j = 1;
var Img = document.getElementsByTagName("img");

for (var i = 0; i < Img.length; i++) {	
	if (Img[i].className == 'imgchair') {
		if ( j == 4 ) { j = 1; }
		Img[i].setAttribute("src", '../../images/img'+j+'.jpg'); 
		j++;
	}
	}
}