JavaScript

2013-10-15T14:17:57Z

KevinPas:

'''JavaScript''' is a [[programming language]] used for [[website|web]] development. While it is primarily used as a scripting language, it has some [[object-oriented]] features.<ref>[http://mckoss.com/jscript/object.htm Object Oriented Programming in JavaScript] - Mike Koss</ref> It is used mainly<ref>For server side and desktop usage see http://vertx.io/ and http://nodejs.org/</ref> for [[client-side]] programming; for a good [[server-side]] language, see [[PHP]].
In a [[web browser]], JavaScript has access to the content of [[HTML]] documents.<ref>David Flanagan, ''Javascript: The definitive guide'', page 6</ref>

==Arrays==

JavaScript doesn't have the same kind of arrays as [[Java]]; this is one of the differences between the two languages.
In JavaScript, the standard array notation is used, but internally data is stored in a [[hash table]].

==Visibility of class members==
There are two sets of variables associated with any object you define in JavaScript.
The first set of variables defined with the <code>this</code> keyword, are all public. The second set of variables, defined with the <code>var</code> keyword, are private. You can even use the same name for a public and private variable, and JavaScript can tell them apart.

===Accessing public and private variables===
Use regular dot notation to get the public variables of an object
* shape.size
Within class functions, use this to get a public variable, and '''omit''' to get a private variable!

== Example Code ==
The following example can be used to disable a form button, for example, to prevent double-posting on a forum.
<pre>// Following code licensed CC-SA

function ref(object)
{
if (document.getElementById) { return document.getElementById(object); }
else if (document.all) { return eval('document.all.' + object); }
else { return false; }
}

function setButton(btnObject)
{
if ( document.post.btnName && document.post.btnValue )
{
document.post.btnName.value = btnObject.name;
document.post.btnValue.value = btnObject.value;
}
else if ( document.all.btnName && document.all.btnValue )
{
document.all.btnName.value = btnObject.name;
document.all.btnValue.value = btnObject.value;
}

var postForm = ref('post');
postForm.submit();
return true;
}</pre>
To make use of this function, add it to the JavaScript used by your form, and then add the following to the button you wish to disable:
<pre>onClick="setButton(this);"</pre>

==Notes==
<references />

==External Links==
[http://www.webteacher.com/javascript/ Javascript Tutorial]
[[Category:Scripting Languages]]

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JavaScript