//initialization, browser, os detection
var d, dom, nu='', brow='', ie, ie4, ie5, ie5x, ie6, ie7;
var ns4, moz, moz_rv_sub, release_date='', moz_brow, moz_brow_nu='', moz_brow_nu_sub='', rv_full=''; 
var mac, win, old, lin, ie5mac, ie5xwin, konq, saf, op, op4, op5, op6, op7;

d=document;
n=navigator;
nav=n.appVersion;
nan=n.appName;
nua=n.userAgent;
old=(nav.substring(0,1)<4);
mac=(nav.indexOf('Mac')!=-1);
win=( ( (nav.indexOf('Win')!=-1) || (nav.indexOf('NT')!=-1) ) && !mac)?true:false;
lin=(nua.indexOf('Linux')!=-1);
// begin primary dom/ns4 test
// this is the most important test on the page
if ( !document.layers )
{
dom = ( d.getElementById ) ? d.getElementById : false;
}
else { 
dom = false; 
ns4 = true;// only netscape 4 supports document layers
}
// end main dom/ns4 test

op=(nua.indexOf('Opera')!=-1);
saf=(nua.indexOf('Safari')!=-1);
konq=(!saf && (nua.indexOf('Konqueror')!=-1) ) ? true : false;
moz=( (!saf && !konq ) && ( nua.indexOf('Gecko')!=-1 ) ) ? true : false;
ie=((nua.indexOf('MSIE')!=-1)&&!op);
if (op)
{
str_pos=nua.indexOf('Opera');
nu=nua.substr((str_pos+6),4);
brow = 'Opera';
}
else if (saf)
{
str_pos=nua.indexOf('Safari');
nu=nua.substr((str_pos+7),5);
brow = 'Safari';
}
else if (konq)
{
str_pos=nua.indexOf('Konqueror');
nu=nua.substr((str_pos+10),3);
brow = 'Konqueror';
}
// this part is complicated a bit, don't mess with it unless you understand regular expressions
// note, for most comparisons that are practical, compare the 3 digit rv nubmer, that is the output
// placed into 'nu'.
else if (moz)
{
// regular expression pattern that will be used to extract main version/rv numbers
pattern = /[(); \n]/;
// moz type array, add to this if you need to
moz_types = new Array( 'Firebird', 'Phoenix', 'Firefox', 'Galeon', 'K-Meleon', 'Camino', 'Epiphany', 
'Netscape6', 'Netscape', 'MultiZilla', 'Gecko Debian', 'rv' );
rv_pos = nua.indexOf( 'rv' );// find 'rv' position in nua string
rv_full = nua.substr( rv_pos + 3, 6 );// cut out maximum size it can be, eg: 1.8a2, 1.0.0 etc
// search for occurance of any of characters in pattern, if found get position of that character
rv_slice = ( rv_full.search( pattern ) != -1 ) ? rv_full.search( pattern ) : '';
//check to make sure there was a result, if not do nothing
// otherwise slice out the part that you want if there is a slice position
( rv_slice ) ? rv_full = rv_full.substr( 0, rv_slice ) : '';
// this is the working id number, 3 digits, you'd use this for 
// number comparison, like if nu >= 1.3 do something
nu = rv_full.substr( 0, 3 );
for (i=0; i < moz_types.length; i++)
{
if ( nua.indexOf( moz_types[i]) !=-1 )
{
moz_brow = moz_types[i];
break;
}
}
if ( moz_brow )// if it was found in the array
{
str_pos=nua.indexOf(moz_brow);// extract string position
moz_brow_nu = nua.substr( (str_pos + moz_brow.length + 1 ) ,3);// slice out working number, 3 digit
// if you got it, use it, else use nu
moz_brow_nu = ( isNaN( moz_brow_nu ) ) ? moz_brow_nu = nu: moz_brow_nu;
moz_brow_nu_sub = nua.substr( (str_pos + moz_brow.length + 1 ), 8);
// this makes sure that it's only the id number
sub_nu_slice = ( moz_brow_nu_sub.search( pattern ) != -1 ) ? moz_brow_nu_sub.search( pattern ) : '';
//check to make sure there was a result, if not do nothing
( sub_nu_slice ) ? moz_brow_nu_sub = moz_brow_nu_sub.substr( 0, sub_nu_slice ) : '';
}
if ( moz_brow == 'Netscape6' )
{
moz_brow = 'Netscape';
}
else if ( moz_brow == 'rv' || moz_brow == '' )// default value if no other gecko name fit
{
moz_brow = 'Mozilla';
} 
if ( !moz_brow_nu )// use rv number if nothing else is available
{
moz_brow_nu = nu;
moz_brow_nu_sub = nu;
}
if (n.productSub)
{
release_date = n.productSub;
}
}
else if (ie)
{
str_pos=nua.indexOf('MSIE');
nu=nua.substr((str_pos+5),3);
brow = 'Microsoft Internet Explorer';
}
// default to navigator app name
else 
{
brow = nan;
}
op5=(op&&(nu.substring(0,1)==5));
op6=(op&&(nu.substring(0,1)==6));
op7=(op&&(nu.substring(0,1)==7));
ie4=(ie&&!dom);
ie5=(ie&&(nu.substring(0,1)==5));
ie6=(ie&&(nu.substring(0,1)==6));
ie7=(ie&&(nu.substring(0,1)==7));
// default to get number from navigator app version.
if(!nu) 
{
nu = nav.substring(0,1);
}
/*ie5x tests only for functionavlity. dom or ie5x would be default settings. 
Opera will register true in this test if set to identify as IE 5*/
ie5x=(d.all&&dom);
ie5mac=(mac&&ie5);
ie5xwin=(win&&ie5x);