//Retrieving the tracking value 
var affiliateTrackingValue = Affiliate_GetTrackingValue();

//Verifying that the tracking value exists
if(affiliateTrackingValue != null)
{         
    //Persisting the tracking value
    Affiliate_CreateTrackingCookie(affiliateTrackingValue); 
}  

function Affiliate_CreateTrackingCookie(trkValue) 
{
    var date = new Date();
	date.setDate(date.getDate() + 365);
	var expires = '; expires=' + date.toGMTString();
    document.cookie = 'AID=' + trkValue + expires + '; path=/';
}

function Affiliate_GetTrackingValue()
{
    var queryStringValue = null;
    var queryString = window.location.search.substring(1);
    var queryStringVariables = queryString.split('&');
            
    for (var i = 0; i < queryStringVariables.length; i++) 
    {
        var nameValuePair = queryStringVariables[i].split('=');
        var name = nameValuePair[0];
        var value = nameValuePair[1];
                    
        if (name.toLowerCase() == 'aid') 
	{
            queryStringValue = value;
            break; 
        }
    } 
    
    return queryStringValue;
}