Ways to define global variables with JavaScript

What is the correct way to create a global variable in JavaScript that is available throughout the entire HTML document? Is it possible to access a variable declared in one script from another?

Answer №1

"Avoid doing this at all costs," is the best advice. Cluttering the overall scope can lead to negative consequences, especially if you need guidance on how to do it (typically indicating that you're looking for an easy fix, which is likely not the appropriate one). What precisely is your end goal here?

If you absolutely must proceed, consider:

  • declaring it outside of any specific function
  • omitting the use of the var keyword
  • utilizing window.variable = value

Answer №2

Define a variable at the global scope, making it available for use in all scripts.

Answer №3

Global variables can be declared in multiple ways such as using the var keyword outside of a function's scope, assigning a variable without using var, or directly assigning a property to the window object.

<script>
var global1 = 'foo';
global2 = 'bar';
window.global3 = 'baz';
function f() {
    var not_global;
}
</script>

Answer №4

Make sure to declare a variable within a script tag prior to running any other scripts.

<script type="text/javascript">
   var greeting = "hello world";
</script>

Answer №5

To define your variable, insert it into a <script> tag, ensuring it is situated within the <body> tag to ensure proper execution by the browser!

Another method could be utilizing a cookie.

Answer №6

In Javascript, any variable that is declared outside of a function or class is considered a global variable.

For instance:

<script>
    var myGlobalVar;
    function someFunction() {
        var myLocalVar;
    }
</script>

Answer №7

Do you want it to look like this?

   let Animal = {
       Tiger: Type
   }

If so, you can refer to it in the following way:

Animal.Tiger

Additionally, you have the option to assign values:

Animal.Tiger = "wild animal"

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