JavaScript
About JavaScript
JavaScript is a scripting language, invented by NetScape. It was originally
named LiveScript. After the introduction of the Java
programming language by Sun Microsystems, NetScape changed its name to
JavaScript. Despite the confusing name similarity, JavaScript
has nothing to do with Java whatsoever.
Java is a full, standalone programming language that needs a compiler.
Java programs can run on any hardware platform (that supports the Java
environment). Often Java applets, small programs with limited
functionality, are included on a web page. These applets need to be downloaded
separately, much like images on a page.
JavaScript on the other hand, is a scripting language. It needs
an interpreter, not a compiler. Javascript "programs" are often included
within the source of a web page.
More and more pages on the World Wide Web use JavaScript. Often it is used
to create dynamic effects on pages, or to add complex functionality to
data-entry forms.
Although JavaScript has a basic protection scheme against privacy violation,
many people think this scheme isn't watertight.
Enabling JavaScript
You can configure AWeb to
use JavaScript or to ignore it. If you are concerned about your privacy,
you should disable JavaScript usage. Note that many pages will not look or
work the way they were designed if you disable JavaScript usage.
Breaking JavaScript programs
You might want to break a JavaScript program if it seems to run too long.
The Control / Break JavaScript menu item allows you
to do so. It will also cancel all outstanding timeout events, these are
often used to create a running text on a page.
If the menu is not available or doesn't seem to work, you should try the
keyboard shortcut for the menu item (by default: RightAmiga-X).
Many pages on the web use JavaScript to automatically open a banner or
advertisement window every time you visit the page. If you find this
annoying, you have the option
to suppress these windows without disabling JavaScript altogether.
This options disables the window.open() function if it would open
a new window, in the following cases: when the statement is run directly from
the page source (interpreted while parsing the page), when it is run as the result
of a <BODY ONLOAD="statement"> or
<BODY ONUNLOAD="statement"> tag, or when it
is run as the result of a setTimeout() run in these places. Opening
a new window as a result of a link or a button is not affected.
Because a failure of the window.open() function might result in more
errors (no such property), error messages are disabled for the remainder of the
script, regardless of the setting of the
Show JavaScript errors option.
Showing JavaScript error messages
Some JavaScript programs generate error messages, either because they are
faulty programs, or because they refer to components not available in this
version of AWeb. If these error messages annoy you, you can
turn these off. With error
messages turned off, the program still stops in error but you won't see the
error message.
Programmers
If you like to add JavaScript to your own pages, AWeb offers you two
bonus features. There is a standalone
JavaScript interpreter, and there is the unique
debugger.
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