function Pos(lay,cx,cy) {
if (navigator.appName=="Microsoft Internet Explorer") {
leftLayer = (document.body.clientWidth /2)-cx;
topLayer = (document.body.clientHeight /2)+cy;
}
if (navigator.appName=="Opera") {
leftLayer = (document.body.clientWidth /2)-cx;
topLayer = (document.body.clientHeight /2)+cy;
}
if (navigator.appName=="Netscape") {
leftLayer = (document.body.clientWidth /2)-(cx+1);
topLayer = (document.body.clientHeight /2)+(cy+15);
}
document.getElementById(lay).style.left = leftLayer
document.getElementById(lay).style.top = topLayer
}


function Show(lay) {
document.getElementById(lay).style.visibility = "visible"
}
function Hide(lay) {
document.getElementById(lay).style.visibility = "hidden"
}
function PositionLayer() {
Pos('back',370,245);
Pos('next',-203,245);
Pos('img_mini_back',350,99);
Pos('img_mini_next',-160,99);
Pos('logo',250,-265);
Pos('menu',320,-320);
}
function VisibleLayer() {
Show('next');
Show('back');
Show('logo');
Show('window');
Show('menu');
}

var in_drag = false;
var in_drag_counter = 0;
function init_move_layer(form){
   var i, coll = document.getElementsByTagName( "DIV" );
   titlediv = document.getElementById(form);
   for( i = 0; i < coll.length; i ++ ){
       if( coll[ i ].getAttribute("drag") == 1 ){
           coll[ i ].onmousedown = function( evnt ){
               evnt = evnt || event;
               in_drag = [ this, evnt.offsetX || evnt.layerX, evnt.offsetY || evnt.layerY ];
               this.style.zIndex = ++in_drag_counter;
           }
       }
   }
   document.onmouseup = function(){
       in_drag = false;
   }
   document.onmousemove = function( evnt ){
       if( ! in_drag ){
           return false;
       }
       evnt = evnt || event;
       titlediv.style.left = ( document.body.scrollLeft + ( evnt.x || evnt.clientX ) - in_drag[ 1 ] ) + "px";
       titlediv.style.top  = ( document.body.scrollTop  + ( evnt.y || evnt.clientY ) - in_drag[ 2 ] ) + "px";
   }
}
// <div style="background:purple;" drag=1></div>
// <script type="text/javascript">
// <!-- //
// init();
// // -->
// </script>