How Can I Access Variables Defined in One JavaScript File from Another?

Accessing Variables Across Files in JavaScript

Can you access variables from different JavaScript files? Yes, it's possible to use a variable defined in a file like first.js within another file like second.js.

Global Scope and Access

In JavaScript, if a variable is declared in the global scope (i.e., not within a function), it becomes available to all scripts loaded after it has been defined. This means that a variable named colorCodes in first.js can be accessed in second.js.

Example Code

Here's an example:

<code class="javascript">// first.js
var colorCodes = {
  back  : "#fff",
  front : "#888",
  side  : "#369"
};</code>

<code class="javascript">// second.js
alert(colorCodes.back); // alerts "#fff"</code>

Load Order and Script Tags

In the HTML file, ensure that first.js is loaded before second.js for the variable to be available in the second script:

<code class="html"><script type="text/javascript" src="first.js"></script>
<script type="text/javascript" src="second.js"></script></code>

Alternative Approach

You can also store the variable on the window object (or this in the global scope) to access it:

<code class="javascript">// first.js
window.colorCodes = {
  // ... same object as before
};</code>

<code class="javascript">// second.js
alert(window.colorCodes.back); // alerts "#fff"</code>

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