Firefox addon on Tab

I am opening a tab with same url with different-different request but it persist old request as well with new request.
I want open a tab with my new request and old request should be disposed.
this is m code
var pageUrl = “autofill.html”;
var userid=resp.user_id;
var userdevicetoken=resp.userdevicetoken;
var useraddress_data=useraddressdata;
var usercc_data=useraccdata;
tabs.on(“ready”, function(tab)
{
var worker ="" ;
worker = tab.attach({
contentScriptFile: [self.data.url(“jquery.min.js”),self.data.url(“CallsClasses.js”),self.data.url(“aes.js”),self.data.url(“crypt/sha1.js”),self.data.url(“crypt/pbkdf2.js”),self.data.url(“lightbox.js”),self.data.url(“commonclasees.js”),self.data.url(“countries.json”)]
});

					worker.port.emit('send_key_details',userid,userdevicetoken,useraddressdata,useraccdata);
					worker.port.on('action',function(resp)
					{
						switch(resp.action)
						{	
							case "register_user_address":
								console.log("register_user_address Domain Request"+JSON.stringify(resp.data));
								addItem("registered_useraddress",resp.data);
							break;
							case "register_user_cc":
								console.log("register_user_cc Domain Request"+JSON.stringify(resp.data));
								addItem("registered_cc",resp.data);
							break;
							 case "update_register_user_address":
								console.log("updated update_register_user_address Request"+JSON.stringify(resp.data));
								update_items("registered_useraddress","localtime_registered_useraddress",resp.data,resp.uniqueid,resp.user_id);
							break;
							case "delete_register_user_address":
								console.log("Deleted delete_register_user_address Request"+JSON.stringify(resp.uniqueid));
								delete_items("registered_useraddress","localtime_registered_useraddress",resp.uniqueid,resp.user_id);
							break; 
							case "update_register_user_cc":
								console.log("updated register_user_cc Request"+JSON.stringify(resp.data));
								update_items("registered_cc","localtime_registered_cc",resp.data,resp.uniqueid,resp.user_id);
							break;
							case "delete_register_user_cc":
								console.log("Deleted register_user_cc Request"+JSON.stringify(resp.uniqueid));
								delete_items("registered_cc","localtime_registered_cc",resp.uniqueid,resp.user_id);
							break;
						}					
					});
				});
				tabs.open(pageUrl);

but it hold previous request as well , How to detach or garbage old request