Flash cards
Review the key moves
What is the main idea behind HTML JavaScript?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
___.getElementById("demo").innerHTML = "Hello JavaScript!";Put the learning moves in the order that makes the concept easiest to apply.
JavaScript makes HTML pages more dynamic and interactive.
The HTML <script> Tag
The HTML <script> tag is used to define a client-side script (JavaScript).
The <script> element either contains script statements, or it points to an external script file through the src attribute.
Common uses for JavaScript are image manipulation, form validation, and dynamic changes of content.
To select an HTML element, JavaScript most often uses the document.getElementById() method.
This JavaScript example writes "Hello JavaScript!" into an HTML element with id="demo":
Example
<script>
document.getElementById("demo").innerHTML = "Hello JavaScript!";
</script>Live preview
Tip
You can learn much more about JavaScript in our JavaScript Tutorial .
A Taste of JavaScript
Here are some examples of what JavaScript can do:
document.getElementById("demo").innerHTML = "Hello JavaScript!";document.getElementById("demo").style.fontSize = "25px";
document.getElementById("demo").style.color = "red";
document.getElementById("demo").style.backgroundColor = "yellow";document.getElementById("image").src = "picture.gif";The HTML <noscript> Tag
The HTML <noscript> tag defines an alternate content to be displayed to users that have disabled scripts in their browser or have a browser that doesn't support scripts:
Example
<script>
document.getElementById("demo").innerHTML = "Hello JavaScript!";
</script>
<noscript>Sorry, your browser does not support JavaScript!</noscript>Live preview
HTML Script Tags
| Tag | Description |
|---|---|
| <script> | Defines a client-side script |
| <noscript> | Defines an alternate content for users that do not support client-side scripts |
For a complete list of all available HTML tags, visit our HTML Tag Reference .