CODEWITHSUNDEEP
javascriptjqueryhtml
Sana Joseph
Sana Joseph

Reputation: 1948

How to keep a variables's value in javascript

I'm a page that redirects to itself. (With next day and previous day arrows) At document.ready the page displays the new day.

The days are stored in a localStorage like this :

for(var i = 0;i<status.length;i++)
  {
      localStorage["Day" + i] = status[i].name;
  }

I want the default day that shows every time is "Day0" then when the user clicks next or previous the other day is showed. 

    $(document).ready(function () {
           $("#CurrentDay").empty();
           $("#CurrentDay").append(GetCurrentDay());
        });

   function GetCurrentDay() {
   localStorage["CurrentDay"] = localStorage["Day0"];
   return localStorage["CurrentDay"];
}

I made the arrows call these functions: 

  function GoToNextDay() {
    if (i != localStorage["SchoolDays"]+1) {
        i = i + 1;
        localStorage["CurrentDay"] = localStorage["Day" + i];
    }
    else {
        localStorage["CurrentDay"] = localStorage["Day" + 0];
    }
}

 function GoToPrevDay() {
    if (i != 0) {
        i = i - 1;
        localStorage["CurrentDay"] = localStorage["Day" + i];
    }
    else {

    localStorage["CurrentDay"] = localStorage["Day" + localStorage["SelectedDaysNumber"]];
    }
}

I'm wondering how can I store the value "i" coz when I initialize it with "0" at the beginning of the script, it keeps returning to 0 whenever the page is called, and if I made it with no value how can I know the place I'm starting at ?

Upvotes: 0

Views: 411

Answers (3)

Eyal Alsheich
Eyal Alsheich

Reputation: 477

you can either use a hash (#) in the url to let your script know what day you are on now, or you can save that information in a cookie.

note that if you use a hash symbol in the URL you can actualy send a link to someone else to a specific day where as in cookies its a per "session" basis meaning only that user's browser will remember what day is active at the moment.

so for example:

www.example.com/#Day0

will be the URL for Day0

www.example.com/#Day1

will be the URL for Day1

then in your code you need to do something like this:

var current_day = window.location.hash;

and use that variable to init your array.

whenever someone clicks to go to another day simply do a history push to the location like 

var url = "#" + day_to_display;
if (history.pushState)
  history.pushState("", "", url);
else
  window.location = url;

Upvotes: 1

WolvDev
WolvDev

Reputation: 3226

You can use localStorage or globalStorage to store the data:

if(typeof localStorage['userName'] === "undefined") {
    // defining the localStorage variable
    localStorage.setItem('userName', 'taranfx');
}

alert("Your user is: " + localStorage.getItem('userName'));

OR you can use cookies to store the value even after refresh of the page:

Cookies can be created, read and erased by JavaScript. They are accessible through the property document.cookie. Though you can treat document.cookie as if it's a string, it isn't really, and you have only access to the name-value pairs.

If I want to set a cookie for with a name-value pair 'ppkcookie1=testcookie' that expires in seven days from the moment I write this sentence, I do

document.cookie =
  'ppkcookie1=testcookie; expires=Thu, 2 Aug 2001 20:47:11 UTC; path=/'
  1. First the name-value pair ('ppkcookie1=testcookie')
  2. then a semicolon and a space
  3. then the expiry date in the correct format ('expires=Thu, 2 Aug 2001 20:47:11 UTC')
  4. again a semicolon and a space
  5. then the path (path=/)

This is a very strict syntax, don't change it!

Also, even though it looks like I'm writing this whole string to the string document.cookie, as soon as I read it out again I only see the name-value pair:

ppkcookie1=testcookie

http://www.quirksmode.org/js/cookies.html

Upvotes: 3

Tel&#233;mako
Tel&#233;mako

Reputation: 673

Store it in localStorage. When launching the script for the first time, check if typeof localStorage['your_var'] == "undefined", if true set it to 0, if false, use that value.

Upvotes: 1

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