Are JavaScript variable names case-sensitive?

Javascript variable naming is case-sensitive. All JavaScript variables must be identified by unique names. These unique names are called identifiers; identifiers can be short names or more descriptive names.

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

Are JavaScript variable names case-sensitive?

Javascript variable naming is case-sensitive.

JavaScript variables are containers that store data values.

JavaScript Identifiers

All JavaScript variables must be identified by a unique name.

These unique names are called identifiers.

Identifiers can be short names (such as x and y), or more descriptive names (age, sum, totalVolume).

The general rules for constructing variable names (unique identifiers) are:

• Names can contain letters, numbers, underscores, and dollar signs

• The name must start with a letter

• The name can also start with $ and _ (but we won’t do that in this tutorial)

• Names are case-sensitive (y and Y are different variables)

• Reserved words (such as JavaScript keywords) cannot be used as variable names

Tip: JavaScript identifiers are case-sensitive.

Assignment Operator

In JavaScript, the equal sign (=) is the assignment operator, not the "equals" operator.

Note: The "equal" operator in JavaScript is ==.

Declaring (Creating) 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 learning:《javascript basic tutorial》

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