function checkBrowser() {
    var agent = navigator.userAgent.toLowerCase();
    this.major = parseInt(navigator.appVersion);
    this.minor = parseFloat(navigator.appVersion);
    this.ns  = ((agent.indexOf('mozilla')!=-1) && ((agent.indexOf('spoofer')==-1) && (agent.indexOf('compatible') == -1)));
    this.ns2 = (this.ns && (this.major == 2));
    this.ns3 = (this.ns && (this.major == 3));
    this.ns4b = (this.ns && (this.minor < 4.04));
    this.ns4 = (this.ns && (this.major >= 4));
    this.ie   = (agent.indexOf("msie") != -1);
    this.ie3  = (this.ie && (this.major == 2));
    this.ie4  = (this.ie && (this.major >= 4));
    this.op3 = (agent.indexOf("opera") != -1);
}
var bw = new checkBrowser();
var path_img = "image/menu/";
if(bw){
    btn1_up = new Image();
    btn1_up.src = path_img + "about_off.gif";
    btn1_dn = new Image();
    btn1_dn.src = path_img + "about_over.gif";

    btn2_up = new Image();
    btn2_up.src = path_img + "books_off.gif";
    btn2_dn = new Image();
    btn2_dn.src = path_img + "books_over.gif";
	
	btn3_up = new Image();
    btn3_up.src = path_img + "publish_off.gif";
    btn3_dn = new Image();
    btn3_dn.src = path_img + "publish_over.gif";

    btn4_up = new Image();
    btn4_up.src = path_img + "service_off.gif";
    btn4_dn = new Image();
    btn4_dn.src = path_img + "service_over.gif";
	
	btn5_up = new Image();
    btn5_up.src = path_img + "yours_off.gif";
    btn5_dn = new Image();
    btn5_dn.src = path_img + "yours_over.gif";

}
var selected = "btn1_img";

function highlight(imageName, fileName) {
    if(bw) {
        document.images[imageName].src = eval(fileName + ".src");
    }
}