Declaring (Creating) JavaScript Variables

Creating a variable in JavaScript is called "declaring" a variable. You declare a JavaScript variable with the var keyword: var carName;

After this declaration, the variable has no value. (Technically it has the value of undefined.) To assign a value to the variable, use the equal sign: carName = "Volvo";

You can also assign a value to the variable when you declare it: var carName = "Volvo";

In the example below, we create a variable called carName and assign the value "Volvo" to it. Then we "output" the value inside an HTML paragraph with id="demo":

HTML file:	Displayed by browser:
<body> <h1>JavaScript Variables</h1> <p>Create a variable, assign a value to it, and display it:</p> <p id="demo"></p> <script> var carName = "Volvo"; document.getElementById("demo").innerHTML = carName; </script> </body>	JavaScript Variables Create a variable, assign a value to it, and display it:

HTML file:

Displayed by browser:

<body>
<h1>JavaScript Variables</h1>
<p>Create a variable, assign a value to it, and display it:</p>
<p id="demo"></p>
<script>
var carName = "Volvo";
document.getElementById("demo").innerHTML = carName;
</script>
</body>

JavaScript Variables

Create a variable, assign a value to it, and display it:

It's a good programming practice to declare all variables at the beginning of a script.