CODEWITHSUNDEEP
javascripthtml
Steven Tran
Steven Tran

Reputation: 114

How to global a js var in a function?

It is possible to global a variable inside a function, if not, how can I access a var in function b from function a.

var money;
var moneyInput = document.getElementById('input');

function check(){
if (moneyInput.value == "") {
    money = 100;
}                   

function hit() {
    document.write(money) // will this money var be 100 or undefined?
}

Upvotes: 0

Views: 87

Answers (7)

Oen44
Oen44

Reputation: 3206

Just declare that variable outside function and then use it inside of that function.

P.S Please, post some code that you tried already. 

let a = 5;
let b = 0; // Declare global variable

function printAB(_b) {
  b = _b; // Set new value through this function
  console.log(a, b);
}

function printBC() {
  let c = 7;
  console.log(b, c); // Get b variable
}

printBC(); // 0, 7 // b = 0
printAB(2); // 5, 2
printBC(); // 2, 7 // b = 2

Edit

With code you provided, answer is simple. Variable money can be equal 100 or be undefined, that depends if function hit will be called before function check.

Upvotes: 2

William Valhakis
William Valhakis

Reputation: 370

/* 1 */

var a = 'sample text';

function one() {
  a = 'modified text';
}

function two() {
  console.log(a);
}

one();
two();

/* 2 */

function one(callback) {
  var a = 'sample text callback';
  callback(a);
}

function two() {
  one(function(a) {
    console.log(a);
  });
}

two();

/* 3 */

var one = new Promise(function(resolve, reject) {
  var a = 'sample text promise';
  resolve(a);
});

function two() {
  one.then(function(a) {
    console.log(a);
  });
}

two();

/* 4 */

var myGlobals = {};

function one() {
  myGlobals.a = 'sample text';
}

function two() {
  console.log(myGlobals.a);
}

one();
two();

Upvotes: 1

Tukan
Tukan

Reputation: 2333

Declaring the variable on the outer scope and using it inside should solve your problem. However if you insist on creating a variable on the global scope you can do the following;

window.VAR_NAME = 'foo';

By doing so you are actually creating a global variable VAR_NAME and it now has the value foo.

Upvotes: 1

Jonas Wilms
Jonas Wilms

Reputation: 138257

You can assign a value to the global object ( window in browsers):

function a(){
  window.test="test";
}
function b(){
 console.log(test);
}
a(),b();

Upvotes: 1

Baruch
Baruch

Reputation: 2428

Assign a variable without using var, let, or const

var foo = 'bar';

function fn() {
  console.log(foo);
  bar = 'xyz';
}

fn()

console.log(bar)

Repl: https://repl.it/languages/javascript

Upvotes: 1

Raphael Martin
Raphael Martin

Reputation: 67

You should declare the variable outside of the function scope:

var myGlobalVar = "foo";

function a(){
   var myLocalVar = 'bar';
   alert(myGlobalVar); //shows foo
   alert(myLocalVar); //shows bar
}

function b(){
   var myLocalVar = 'baz';
   alert(myGlobalVar); //shows foo too
   alert(myLocalVar); //shows baz
}

Upvotes: 1

user2182349
user2182349

Reputation: 9782

If you assign a value to an undeclared variable in a function it will be created as a global variable.

Upvotes: 1

Related Questions