function init() {
IE = (document.all);
NC = (document.layers);
Opera = (document.getElementById);
Mozilla = (navigator.appName);
isDOM=document.getElementById; //DOM1 browser (MSIE 5+, Netscape 6, Opera 5+)
isOpera=isOpera5=window.opera && isDOM; //Opera 5+
isOpera6=isOpera && window.print; //Opera 6+
isOpera7=isOpera && document.readyState; //Opera 7+
isMSIE=document.all && document.all.item && !isOpera; //Microsoft Internet Explorer 4+
isMSIE5=isDOM && isMSIE; //MSIE 5+
isNetscape4=document.layers; //Netscape 4.*
isMozilla=isDOM && navigator.appName=="Netscape"; //Mozilla или Netscape 6.*

}
function showLayer_book(lay) {
init();
//mousex = 0;
//mousey = 0;
if(isNetscape4) document.captureEvents(Event.MOUSEMOVE)
if(isMSIE || isOpera7){
  document.onmousemove=function(){
    mousex=event.clientX+document.body.scrollLeft;
    mousey=event.clientY+document.body.scrollTop;
    return true
  }
}else if(isOpera){
  document.onmousemove=function(){
    mousex=event.clientX;
    mousey=event.clientY;
    return true
  }
}else if(isNetscape4 || isMozilla){
  document.onmousemove=function(e){
    mousex = e.pageX+5;
    mousey = e.pageY+5;
    return true
  }  
}
x = mousex;
y = mousey ;
if(IE) eval('document.all[lay].style.top = y')
if(NC) eval('document.layers[lay].top = y')
if(Opera) eval('document.getElementById(lay).style.top  = y')
if(IE) eval('document.all[lay].style.left = x')
if(NC) eval('document.layers[lay].left = x')
if(Opera) eval('document.getElementById(lay).style.left  = x')

if(IE) eval('document.all[lay].style.visibility = "visible"')
if(NC) eval('document.layers[lay].visibility = "visible"')
if(Opera) eval('document.getElementById(lay).style.visibility = "visible"')

}
function hiddenLayer(lay) {
NC = (document.layers);
IE = (document.all);
Opera = (document.getElementById);
if(IE) eval('document.all[lay].style.visibility = "hidden"');
if(NC) eval('document.layers[lay].visibility = "hidden"');
if(Opera) eval('document.getElementById(lay).style.visibility = "hidden"');
}