HTML Scripting (Client-side Scripting)

With HTML scripting (or some client-side scripting) are scripts (usually JavaScript) indicated in the HTML of a document. The scripts ensure that the web is interactive. It is however necessary so that the browser supports the script.

HTML Scripting (Client-side Scripting) Introduction

In 1995, Netscape Navigator version 2.0 released, which first offered support for browser scripts in HTML documents. The script was originally Live Script and JavaScript that later.

With the introduction of JavaScript made it possible to static HTML documents to a certain interactivity. In later years, this has led to the launch of Dynamic HTML and then led to further enhance the interactivity of HTML documents.

Microsoft could not lag behind this development and began development of Internet Explorer for a similar script. Because there were small differences, Microsoft took the script under the name JScript. From version 3.0, support Internet Explorer not only JScript as well as VBScript and (up to version 5.x) PerlScript.

The script languages used in HTML documents are also used in other applications. The languages are each discussed in their own lemma.

Browsers And Scripts

Scripts can be located anywhere in an HTML document to be placed. There is a special HTML tag that indicates that a script is. In this tag can specify the scripting language used if nothing is specified, it is understood that the Javascript does.

The scripts in HTML documents was used to communicate with the browser (i.e., not with the document). Most browsers have the option to put Javascript off. Because web pages may contain scripts that require the browser to open pop-ups (usually with advertising), there was the choice for the users to put off the scripting commands.

Support for scripts in the browser was built then. All advanced browsers support Javascript. Support for VBScript is limited to Internet Explorer. Under Windows using Internet Explorer, the default interpreters in Windows were built (jscript.dll and vbscript.dll). In other cases, the interpreter was part of the installation. There are some differences between the browsers in the interpretation of Javascript. Another possible source of differences in interpretation of scripts is to use a different model of the document by the browser (see Document Object Model).

Applications Of Scripts In HTML

Scripts are the browser commands to do something (perform some actions). The browser could respond by, for example, a warning (alert) to show some message to the user. The powerful applications lie in contracts relating to the displayed document, and in using the Document Object Model (DOM) properties in the browser of the document retrieval and adaptation. Commonly used applications are:

* Control of a completed form or validation. With a script, the completed data in a form in a web page is to be checked before the form is sent. Because they control the computer of the user, this is much faster than checking on the web after sending. Moreover, some data on the Web to check, e.g., whether a completed e-mail address already existed before.
* Use of cookies. With help of scripts in the browser, cookies can be placed and read back.
* Retrieving new information. Scripts browser may order that information to be retrieved from the web. This often happens with a new window containing a new document. But it is also possible that the new information is stored as a variable, and then into the existing document that is being processed.
* Adjustments to the style. The style of the elements of the document is used or modified by means of scripts. The applications are endless.
* Dynamic menus (an example of adaptation of style). Many web pages use dynamic menus, so the new user choices will appear as the mouse over a main choice is put.

Events And Bubbling

The interactivity that HTML scripts are provided, based on the collection of events (in English usually called events). There are two causes of events: the user and the browser. The events caused by user input via mouse and keyboard. The events of the browser are related to the collection of new documents (eg the document is loaded “or” the document is now closed “). See also List of HTML events.

The individual elements of a document can be made sensitive to the various events. At the time that such an event then takes place, the element reacts with a task that the script above.

The concept of bubbling is useful in situations where an element of the document is in another element. If the user clicks on a label in a table, is that a click on the image or click on the table? It is primarily a click on the image, but the click is sent to all upper (parent) elements. This process is called passing hot bubbling. In the event that this is undesirable bubbling, the code can be stopped.

~Source: Wikipedia