browserName = navigator.appName;
browserVer = parseInt(navigator.appVersion);
var ver = false
if (browserName == "Microsoft Internet Explorer" && browserVer >= 4) ver = true;
if (browserName == "Netscape" && browserVer >= 3) ver = true;

if (ver){
	for (var i = 1; i<5; i++) {
		eval ("img_" + i + " = new Image()");
		eval ("img_" + i + ".src = '../images/img" + i + "b_present.jpg'");
	}
	load = true;
}


function ON_img(N_img) {
	if (ver && load) {
		eval ("document.img" + N_img + ".src = img_" + N_img + ".src");

	}
}


function OFF_img(N_img) {
	if (ver && load) {
		eval ("document.img" + N_img + ".src = '../images/img" + N_img + "a_present.jpg'");
	}
}