function dlayer() {

  this.ns  = (document.layers)? true : false;
  this.ie  = (document.all)? true : false;
  this.ie4 = (navigator.appVersion.indexOf("MSIE 4.") > 0);

  this.visible_layers = new Array();

  if(this.ns) {
    this.getleft   = dlayer_ns_getleft;
    this.getwidth  = dlayer_ns_getwidth;
    this.getheight = dlayer_ns_getheight;
    this.gettop    = dlayer_ns_gettop;
    this.setleft   = dlayer_ns_setleft;
    this.setwidth  = dlayer_ns_setwidth;
    this.setheight = dlayer_ns_setheight;
    this.settop    = dlayer_ns_settop;
    this.isvisible = dlayer_ns_isvisible;
    this.show      = dlayer_ns_show;
    this.hide      = dlayer_ns_hide;
    this.exists    = dlayer_ns_exists;
    this.fixwidth  = dlayer_void;
    this.settext   = dlayer_ns_settext;
  }
  else if(this.ie) {
    this.getleft   = dlayer_ie_getleft;
    this.getwidth  = dlayer_ie_getwidth;
    this.getheight = dlayer_ie_getheight;
    this.gettop    = dlayer_ie_gettop;
    this.setleft   = dlayer_ie_setleft;
    this.setwidth  = dlayer_ie_setwidth;
    this.setheight = dlayer_ie_setheight;
    this.settop    = dlayer_ie_settop;
    this.isvisible = dlayer_ie_isvisible;
    this.show      = dlayer_ie_show;
    this.hide      = dlayer_ie_hide;
    this.exists    = dlayer_ie_exists;
    if(this.ie4) {
      this.fixwidth  = dlayer_ie4_fixwidth;
    }
    else {
      this.fixwidth  = dlayer_void;
    }
    this.settext   = dlayer_ie_settext;
  }
  else {
    this.getleft   = dlayer_void;
    this.getwidth  = dlayer_void;
    this.getheight = dlayer_void;
    this.gettop    = dlayer_void;
    this.setleft   = dlayer_void;
    this.setwidth  = dlayer_void;
    this.setheight = dlayer_void;
    this.settop    = dlayer_void;
    this.isvisible = dlayer_void;
    this.show      = dlayer_void;
    this.hide      = dlayer_void;
    this.exists    = dlayer_void;
    this.fixwidth  = dlayer_void;
    this.settext   = dlayer_void;
  }

  if(this.ns || this.ie) {
    this.getright  = dlayer_getright;
    this.getbottom = dlayer_getbottom;
  }

}

function dlayer_void() { return false; }


// netscape functions ///////////////////////////////////////////////

function dlayer_ns_getleft(name)          { return document.layers[name].left; }
function dlayer_ns_getwidth(name)         { return document.layers[name].clip.width; }
function dlayer_ns_getheight(name)        { return document.layers[name].clip.height; }
function dlayer_ns_gettop(name)           { return document.layers[name].top; }
function dlayer_ns_setleft(name, value)   { document.layers[name].left = value; }
function dlayer_ns_setwidth(name, value)  { document.layers[name].clip.width = value; }
function dlayer_ns_setheight(name, value) { document.layers[name].clip.height = value; }
function dlayer_ns_settop(name, value)    { document.layers[name].top = value; }
function dlayer_ns_isvisible(name)        { return document.layers[name].visibility != "hide"; }
function dlayer_ns_show(name)             { document.layers[name].visibility = "show"; }
function dlayer_ns_hide(name)             { document.layers[name].visibility = "hide"; }
function dlayer_ns_exists(name)           { if(document.layers[name]) { return true } else { return false; } }

function dlayer_ns_settext(name, text) {
  document.layers[name].document.write(text);
  document.layers[name].document.close();
}

// ie functions /////////////////////////////////////////////////////

function dlayer_ie_getleft(name)          { return document.all[name].style.pixelLeft; }
function dlayer_ie_getwidth(name)         { return document.all[name].offsetWidth; }
function dlayer_ie_getheight(name)        { return document.all[name].offsetHeight; }
function dlayer_ie_gettop(name)           { return document.all[name].style.pixelTop; }
function dlayer_ie_setleft(name, value)   { document.all[name].style.pixelLeft = value; }
function dlayer_ie_setwidth(name, value)  { document.all[name].style.pixelWidth = value; }
function dlayer_ie_setheight(name, value) { document.all[name].style.pixelHeight = value; }
function dlayer_ie_settop(name, value)    { document.all[name].style.pixelTop = value; }
function dlayer_ie_isvisible(name)        { return document.all[name].style.visibility != "hidden"; }
function dlayer_ie_show(name)             { document.all[name].style.visibility = "visible"; }
function dlayer_ie_hide(name)             { document.all[name].style.visibility = "hidden"; }
function dlayer_ie_exists(name)           { if(document.all[name]) { return true } else { return false; } }
function dlayer_ie4_fixwidth(name)        { this.setwidth(name, 1); }
function dlayer_ie_settext(name, text)    { document.all[name].innerHTML = text; }

// common functions /////////////////////////////////////////////////

function dlayer_getright(name)  { return this.getleft(name) + this.getwidth(name); }
function dlayer_getbottom(name) { return this.gettop(name) + this.getheight(name); }