var isDOM=document.getElementById //DOM1 browser (MSIE 5+, Netscape 6, Opera 5+)
  var isMSIE=document.all && document.all.item //Microsoft Internet Explorer 4+
  var isNetscape4=document.layers //Netscape 4.*
  var isOpera=window.opera //Opera
  var isOpera5=isOpera && isDOM //Opera 5+
  var isMSIE5=isDOM && isMSIE //MSIE 5+
  var isMozilla=isNetscape6=isDOM && !isMSIE && !isOpera //Mozilla или Netscape 6.*

  var leftOffset = 0;
  var topOffset = 321;

  if( isMozilla ) {
	leftOffset = 2;
	topOffset = 300;
  } else if( isOpera ) {
	topOffset = 305;
  }

  function cat_show()
  {
    document.getElementById("catalog").style.visibility = "visible";
    document.getElementById("services").style.visibility = "hidden";
    document.getElementById("company").style.visibility = "hidden";
    document.getElementById("catalog").style.left = (screen.availWidth - 830 - (screen.width > 1024 ? (screen.width-1024)/2 : 0) + leftOffset) + 'px';
    document.getElementById("catalog").style.top = topOffset + 'px';
 
  }

  function srvc_show()
  {
    document.getElementById("services").style.visibility = "visible";
    document.getElementById("catalog").style.visibility = "hidden";
    document.getElementById("company").style.visibility = "hidden";
    document.getElementById("services").style.left = (screen.availWidth - 675 - (screen.width > 1024 ? (screen.width-1024)/2 : 0) + leftOffset) + 'px';
    document.getElementById("services").style.top = topOffset + 'px';
    
  }

  function comp_show()
  {
    document.getElementById("company").style.visibility = "visible";
    document.getElementById("catalog").style.visibility = "hidden";
    document.getElementById("services").style.visibility = "hidden";
    document.getElementById("company").style.left = (screen.availWidth - 365 - (screen.width > 1024 ? (screen.width-1024)/2 : 0) + leftOffset) + 'px';
    document.getElementById("company").style.top = topOffset + 'px';
    
  }

  function cat_hide()
  {
    document.getElementById("catalog").style.visibility = "hidden";
    //document.getElementById("services").style.visibility = "hidden";
  }

  function srvc_hide()
  {
    //document.getElementById("catalog").style.visibility = "hidden";
    document.getElementById("services").style.visibility = "hidden";
  }

  function comp_hide()
  {
    document.getElementById("company").style.visibility = "hidden";
    //document.getElementById("services").style.visibility = "hidden";
  }

  function loaded() { // onload

  }