What is Javascript?
by WebAIM
What is JavaScript?
This may best be
answered by defining what JavaScript is NOT. First, it is not HTML. JavaScript
does not use HTML tags or abide by any of the general rules of the HTML language.
You can, however, use JavaScript with HTML on a webpage. Second, JavaScript
is not Java. Although JavaScript is often called Java, the two are not the same.
Java was developed by Sun Microsystems and is a stand-alone programming language.
JavaScript, on the other hand, was developed by Netscape Corporation. Although
similar to Java in syntax, JavaScript is not a stand-alone language; in order
for JavaScript to work, it must be part of a web page that is being displayed
in a browser that understands the JavaScript language. Sun´s Java programming
language can be implemented in webpages as a built in program, whereas JavaScript
scripts are reliant upon the client (visitor´s) computer in order for them to
work.
Once again, JavaScript is not HTML or a version of HTML. It is a distinct,
separate scripting language. HTML is read and processed by the web browser.
When the browser reads JavaScript code within your HTML document, it processes
the code, then displays any output within the web page. The computer reading
the JavaScript must have a JavaScript interpreter, a program that interprets
the script and runs it, and that interpreter must be enabled.
HTML, alone, creates very static pages. There is little user interaction and
little by the way of dynamic content within a particular page. HTML cannot think;
it does not have the capabilities to perform mathematics, store variables, or
dynamically display content. JavaScript allows your web page to ´think´. Although
many server-side scripting programs (such as PHP, JPS, ASP, or ColdFusion) have
the ability to perform such functions, JavaScript can perform these functions
within the client web browser. Because JavaScript is a scripting language, it
allows developers to implement little applications into their pages. These programs
may do things as simple as changing a graphic when the mouse rolls over it to
something as complex as performing advanced mathematical formulas on user input.
posted on Jun 1, 2007
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