JavaScript can be used to create cookies in web browser of the website visitor to track the number of visits by that visitor or new visitor.
JavaScript can be used to detect the name and version of browsers that the visitor is using to browse the web sites, so that, you can manage the JavaScript code handling according to the compatibility standards of that browser.
<script language="javascript" type="text/javascript">
document.write(navigator.userAgent);
</script>
You can validate the data input submitted by any web site user whether he has filled all the input fields correctly. E.g.: email id is valid or not, zip code is valid or not, telephone number is valid or not, user has selected at least any value in HTML select control.
You can create HTML elements dynamically by using JavaScript functions and you can modify its content and CSS styles also.
JavaScript can generate innerHTML for HTML elements dynamically.
JavaScript can also be used to handle the client end events of basic HTML controls like onclick event of button, input text, select dropdowns or list boxes.
JavaScript can used to create small widgets that can be shared in number of web pages.
