function extract_params(theArgName) {

    var domain = document.referrer;

    //extract adw= from url (used in adsense custom urls)
    //just add a adw=<keyword> to the custom url for each keyword you define in adsense)
    var sArgs = location.search.slice(1).split('&');
    for (var i = 0; i < sArgs.length; i++) {
        if (sArgs[i].substring(0, sArgs[i].indexOf('=')) == theArgName) {
            return "adword-" + sArgs[i].substring(sArgs[i].indexOf('=')+1)+':'+domain;
        }
    }


    //no adw parameter...lets try q= (if its a searchengine)
    if ( domain.indexOf('google') > 0 || domain.indexOf('yahoo') > 0 || domain.indexOf('exalead') > 0 || domain.indexOf('.msn.') > 0 ) {
        sArgs = domain.substring(domain.indexOf('?')+1).split('&');
    
        for (var i = 0; i < sArgs.length; i++) {
            if (sArgs[i].substring(0, sArgs[i].indexOf('=')) == 'q') {
                return "search-" + sArgs[i].substring(sArgs[i].indexOf('=')+1)+':'+domain;
            }
        }
    }

    //not a q= parameter from goolge...if its not our own site...we take the whole one as linkid
    if ( domain.indexOf('site-vault.') <= 0 ) {
        return "ref-" + domain;
    }

    return '';
}

function Set_Cookie( name, value, expires, path, domain, secure ) {
var today = new Date();
today.setTime( today.getTime() );
if ( expires ) {
expires = expires * 1000 * 60 * 60 * 24;
}
var expires_date = new Date( today.getTime() + (expires) );
document.cookie = name + "=" +escape( value ) +
( ( expires ) ? ";expires=" + expires_date.toGMTString() : "" ) + 
( ( path ) ? ";path=" + path : "" ) + 
( ( domain ) ? ";domain=" + domain : "" ) +
( ( secure ) ? ";secure" : "" );
}

function Get_Cookie( name ) {
var start = document.cookie.indexOf( name + "=" );
var len = start + name.length + 1;
if ( ( !start ) && ( name != document.cookie.substring( 0, name.length ) ) ) {
return null;
}
if ( start == -1 ) return null;
var end = document.cookie.indexOf( ";", len );
if ( end == -1 ) end = document.cookie.length;
return unescape( document.cookie.substring( len, end ) );
}


function modifyURL(iURL) {
var params = Get_Cookie( 'adw' );
if ( params != '' ) {
if ( iURL.indexOf('?') > 0 ) {
var murl = iURL + '&custom_linkid=' + params;
} else {
var murl = iURL + '?custom_linkid=' + params;
}
} else {
var murl = iURL;
}
return murl;
}

//extract from get-url and set as a cookie
var params = extract_params('adw');
if ( params != '' ) {
Set_Cookie( 'adw', params, '', '/', '', '' );
}