You see other webpages that a button shows who say different things, like click me, log in, sign in and so many button show on webpages. In this session you will learn that how wo display your own buttons on your webpages.
JavaScript makes HTML pages more dynamic and interactive.
Example
My First JavaScript
Click me to display Date and Time
The HTML Tag
The tag is used to define a client-side script (JavaScript).
The element either contains scripting 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 very often use the document.getElementById(id) method.
This JavaScript example writes “Hello JavaScript!” into an HTML element with id=”demo”:
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:
JavaScript can change HTML content
document.getElementById(“demo”).innerHTML = “Hello JavaScript!”;
JavaScript can change HTML styles
document.getElementById(“demo”).style.fontSize = “25px”;
document.getElementById(“demo”).style.color = “red”;
JavaScript can change HTML attributes
document.getElementById(“image”).src = “picture.gif”;
The HTML <noscript> Tag
The <noscript> tag is used to provide an alternate content for users that have disabled scripts in their browser or have a browser that doesn’t support client-side scripts:
Example
document.getElementById(“demo”).innerHTML = “Hello JavaScript!”;
<noscript>Sorry, your browser does not support JavaScript!</noscript>
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 |