Can't get a value from an URL parameter

I'm trying to integrate the Google+ API in my web application which is developed in Angular2 so I can login to the home page using my Google account credentials and without the need to create a new account. I made a clickable html link that has the following href

http://ift.tt/1RtQlvT

Once clicking on it, it demands for permission through my google account and when i authorize, it redirect me to the http://localhost:3000/home?code=4 the problem is that I need the whole code's value so that I can use it to get the Access Token but I don't know why the value appeared then it went hidden in less than a second and just keeping the first letter of the code (which is 4 in this case). The problem that if I go back to the previous page of the browser it will appear again. Any help please?