My project is composed by 2 html pages: 1)index.html, wich contains the login and the registration form. 2)user_logged.html, wich contains all the features of a logged user. Now, what I want to do is a control if the user is really logged, to avoid the case where a user paste a url in the browser and can see the pages of another user. hours as now, if a user paste this url in the browser: www.user_loggato.html?user=x#profile is as if logged in as user x and this is not nice. My html pages both use js files that contains scripts. I decided to create a global variable called logged inizialized to false and change the variable to true when the login is succesfull. The problem is that the variable, remains false. here is the code: var logged=false; (write in the file a.js) while in the file b.js I have: function login() { //if succesfull logged=true; window.location.href = "user_loggato.html?user="+ JSON.parse(str).username + #profilo"; Now with some alerts I found that my variable logged is always false. Why? if I have not explained well or if there is not some information in order to respond to my question let me know.