Getting Globally declared variable value from 1 function to another function

Question

I have a very common question about javascript i have a globally declared variable but how can a function with that variable pass the value in the globally declared variable then use it in the second function??

 var ID;

    function test() {

       $.getJSON('/Test1/GetTestID', function (test) {
                $.each(test, function () {
         ID = this["ID"]
         alert(ID);
    }
    })
    }

    function test1() {
             $.getJSON("/TestSite?Test=" + ID; )
    }

    alert(ID);
    test();
    test1();

Function test alert the ID but when i declare it Globally it was undeclared.

Can someone help me with this??

Thanks

@RC. actually the id came from getJson , now added something .. — Ren Tao
– Ren Tao, Commented Feb 20, 2014 at 6:20
you can't, you have to call test1 in the callback of getJSON — user180100
– user180100, Commented Feb 20, 2014 at 6:22
@RC. so its impossible to pass value on the globally declared variable and fetch it in another Function?? — Ren Tao
– Ren Tao, Commented Feb 20, 2014 at 6:23

Rob M. · Accepted Answer · 2014-02-20 06:24:35Z

1

I think you are expecting getJSON to be synchronous, but it is not. If the calls are dependent you should nest them:

function test() {
       $.getJSON('/Test1/GetTestID', function (test) {
           $.each(test, function () {
              ID = this["ID"]
              $.getJSON("/TestSite?Test=" + ID; )
           })
       })
}

test1 is being called before test has completed its getJSON call

answered Feb 20, 2014 at 6:24

Rob M.

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score 0 · Accepted Answer · 2014-02-20 06:26:11Z

0

Because getJSON is asynchronous, the proper way do perform what you need is to use the returned ID in the callback of getJSON:

function test() {    
    $.getJSON('/Test1/GetTestID', function (test) {
        $.each(test, function () {
            var theId = this["ID"];
            alert(theId);
            test1(theId);
        }
    });
}

function test1(id) {
    $.getJSON("/TestSite?Test=" + id);
}

test();

edited Feb 20, 2014 at 6:26

answered Feb 20, 2014 at 6:24

user180100

4 Comments

Ren Tao Over a year ago

sir the function test1(id) or function test1(theId)?

user180100 Over a year ago

@RenTao some basic tutorial about JS variable scope and function might be a good idea

Ren Tao Over a year ago

just clarifying things sir

user180100 Over a year ago

In test() if theId is 123 then test1(theId) call test1 with the value 123 and in test1 we get 123 as value for id. theId only exists in test() and id only exists in test1.

Preet · Accepted Answer · 2014-02-20 06:28:51Z

0

Try this first you set you id to Zero

    var ID =0;

answered Feb 20, 2014 at 6:28

Preet

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