function get_elem(el)
{
    return document.getElementById(el);
}
function strpos(haystack,needle,offset)  {var i=(haystack+'').indexOf(needle,offset); return i===-1 ? false : i;}

function get_browser() {
    var  browser_agent = navigator.userAgent;
    if        (strpos(browser_agent,"fox/2"))  return "firefox_2";
    else if   (strpos(browser_agent,"fox/3"))  return "firefox_3";
    else if   (strpos(browser_agent,"pera"))   return "opera";
    else if   (strpos(browser_agent,"MSIE 6")) return "ie_6";
    else if   (strpos(browser_agent,"MSIE"))   return "ie";
    else if   (strpos(browser_agent,"hrome"))  return "google_chrome";
    else if   (strpos(browser_agent,"afari"))  return "safari";
    else                                       return browser_agent;
}
function link(str)
{
  return top.location.href=str;
}
function get_elem_height(el)
{
    return document.getElementById(el).clientHeight;
}
function getBodyHeight()
{
    return document.body.offsetHeight;
}