JavaScript var
Statement
JavaScript Statements Reference
Example
Create a variable named carName
with the value "Volvo":
var carName = "Volvo";
More examples are included at the bottom of this page.
Definition and Usage
The var
statement is used to declare variables.
Creating a JavaScript variable is also referred to as "declaring" a variable:
After a variable is declared, it is empty (has no value).
To assign a value to the variable, do the following:
You can also assign a value to the variable when you declare it:
For more information on variables, see our JavaScript Variables tutorial and JavaScript Scope tutorial.
Browser Support
Statement | Chrome | Edge | Firefox | Safari | Opera |
---|---|---|---|---|---|
var | Yes | Yes | Yes | Yes | Yes |
Syntax
Parameter Values
Parameter | Description |
---|---|
varname | Required. Specifies the variable name. The variable name can contain letters, digits, underscores, and dollar signs. The variable name must start with a letter. <br> The variable name can also start with $ and _ (but these are not commonly used). <br> Variable names are case-sensitive (y and Y are different variables). <br> Reserved words (like JavaScript keywords) cannot be used as variable names. |
value | Optional. Specifies the value of the variable. <br> <br> Note: If the variable declaration does not specify a value, it defaults to undefined. |
Technical Details
| JavaScript Version: | 1.0 | | --- | --- |
More Examples
Example
Create two variables x
and y
. Assign x
the value 5 and y
the value 6. Then output the result of x + y
:
var x = 5;
var y = 6;
document.getElementById("demo").innerHTML = x + y;
Example
You can declare multiple variables in one statement.
The statement starts with var and the variables are separated by commas:
var lastName = "Doe",
age = 30,
job = "carpenter";
Example
Using variables in a loop:
var text = "";
var i;
for (i = 0; i < 5; i++) {
text += "The number is " + i + "<br>";
}
Related Pages
JavaScript Tutorial: JavaScript Variables
JavaScript Tutorial: JavaScript Scope