Iframes, or inline frames, allow you to load html files into an existing document. Frames are inline frames that are sometimes referred to as floating frames. One of the main advantages of the iframe tag is that it can be used to load external html or xhtml pages into the current document without distrubing the original page.

This iframe tag was not much popular when introduced because it was not supported by all the major browsers. But now Internet Explorer 4+, Netscape 6+, Firefox, Mozilla, Opera and other modern browsers all support iframes.

A basic iframe tag is :

<iframe></iframe>

However iframe supports a number of attributes like :

src, name, width, height, align, frameborder, scrolling

New html documents can be loaded into the iframe without disrupting the rest of the document. CSS and JavaScript can be used to manipulate properties of the iframe, such as its position and size. JavaScript can also be used to communicate between the document containing the iframe and the document loaded inside it.
So, dynamically the iframe contents can be replaced.

Also the iframes can be kept hidden. the hidden iframes can execute the code and then can send the results to the main document containing it using javascript. Thus, hidden iframes can be used as an alternative ti AJAX. Now-a-days many developers find it easy to use iframes for remote scripting. Remote Scripting is the process by which a client-side application running in the browser and a server-side application can exchange data without reloading the page.

A Validator is a automated program or script to check the validity of the HTML coding of your Web pages. A validator is important tool which ensures that coding is valid as invalid code can impact the accessibility of pages and eventually the website. It is generally used before a website goes live or web pages are posted for public use to make sure that the pages can be read and used by all browsers and search engines. Some validators also check for broken links on the site i.e links which no longer work, and some also spell check your text.

Verifying the consistency and perfection of HTML elements manually is quite a tedious job and it becomes even more arduous when different sets of validation rules, such as those for cascading style sheets (CSS) and Extensible Markup Language (XML) are included in the page. By using a validation program to signalize errors in an organized manner, the HTML user can choose whether to correct code mistakes on a case-by-case basis or correct them globally by using a “find and replace” mechanism within the program.

To start with the clickable-thumbnail, we should first upload simple images to server and thereafter to display the image in a forum

For example – for imageshack {a image hoster} -

Code:

[img]http://img50.imageshack.us/img59/2374/imagename.jpg[/img]

To put in links in text -

Code:

[URL=webisteaddress] website title to be shown [/URL]

Now clickable-thumbnails comprises of both –

Code:

[URL=link to large image] [img] link to small image [/img] [/URL]

This will show the image along with the link.

These codes are one of the important contents that make up a web page that work behind the scenes so you can see the page the way it was designed to show up on your browser. You, the viewer usually are not even aware of them. If they are not written properly, the page does not show up correctly, negating some of the design. If you’ve never seen HTML Codes, right click on your mouse anywhere on this page, then scroll down to view source and click on it. What pops up is the entire page written in HTML Code, including the meta tags .