The advantages of an external stylesheet are:

Reduced bandwidth.For a certain period of time browsers typically only request one copy of your external CSS stylesheet, then caches that copy and won’t request your server for another copy.By refreshing the page, the cache can be over written. Try refreshing the external stylesheet if this doesn’t work.

The bandwidth of the HTML code can reduced using external CSS stylesheets so that html code to be a clearer and contain less redundant style information. To send the file out to the browser, it is required to have a smaller file size and the less bandwidth. For example, if wanted all <td> tags of your web site to be vertically aligned in the center, instead of using <td align=center> for every single <td> tag in your html document, simply define the vertical alignment in the external stylesheet and in your html document, all you will need to use is <td> and all <td> will be vertically aligned.

Easier to maintainYou only need to define it once in external stylesheet,instead of defining a style for a particular element over and over again. By changing one file, the .css file, external stylesheets also enable altering the whole look of a web site.

Using a simple text editor we can create external CSS stylesheets. Most PC’s have Text Pad which is the standard text editor, Mac’s have TextEdit which is the standard text editor. I recommend BBEdit on Macs as a text editor as it has many features a standard text editor doesn’t usually have.

>To create an external CSS stylesheet, open up a new file and enter in the style information for that site. For example (Here is style.css):

In the above example, an external stylesheet named style.css contained within the same directory as the web page, the simplest way to link to style.css is by adding the following code within the head tags as given below: