Did you post that 3 times? I think a mod cleaned it up but if you did, don't double (or tripple) post please.
function send(){
var a= "http://www.onlinevisitors.com/visitorsInfo.php?page=on&title='"+title+"'&browse='"+browse+"'&ip='"+ip+
"'&OSName='"+OSName+"'&browver='"+browver+"'";
}
That doesn't do anything. all it does it sets the variable a to hold the URL. Assuming all the other varaibles exist.