How to define variables in javascript

Creating variables in JavaScript is called "declaring" variables, then we can declare JavaScript variables through the var keyword. The declaration syntax is "var carName;" and the syntax for assigning values ​​to variables is such as "carName. = "porsche";".

The operating environment of this article: windows7 system, javascript version 1.8.5, DELL G3 computer

javascript definition variable writing method

Declare (Create) JavaScript Variables

Creating a variable in JavaScript is called "declaring" a variable.

You can declare JavaScript variables through the var keyword:

var carName;

After declaration, the variable has no value. (Technically, its value is undefined.)

To assign a value to a variable, use the equal sign:

carName = "porsche";

You can assign a value to a variable when you declare it:

var carName = "porsche";

In the above example, we created a variable named carName and assigned the value "porsche" to it.

Then, we "output" the value in the HTML paragraph with id="demo":

Example

<script>
var carName = &quot;porsche&quot;;
document.getElementById("demo").innerHTML = carName; 
</script>

Recommended study: "javascript Advanced Tutorial》

The above is the detailed content of How to define variables in javascript. For more information, please follow other related articles on the PHP Chinese website!