Front End Web Developer

In a nutshell page performance is widely understood as the page load time from the users' perspective, so below are some steps that might improve a page's performance.

Use sprite images whenever possible, try to group small images commonly used in a single file to be requested just once. See how Google uses sprites in Google Maps to make one request instead of one for each small image. See a sprite from Google Maps

Javascripts should be at the bottom of the page, instead of in the head as we use to see out there;

Ensure parallel requests of your JS and CSS files. In order to force the browser to do that, you can optimize the order you include resources in your page. This item can generate its own blog post or even a book so I prefer to suggest you a really good reading about it.

Compress images whenever possible, it makes a difference;

Browser Caching is also very import to be set for static resources like JS and CSS files, images, PDFs and HTML. Caching is set in the HTTP header by informing browsers the expiry date or maximum age. Then browsers can load the last downloaded resource from the cache instead of request it again.

The purpose of each of the HTTP request types when used with a RESTful web service is as follows:

☛ GET: Retrieves data from the server (should only retrieve data and should have no other effect).

☛ POST: Sends data to the server for a new entity. It is often used when uploading a file or submitting a completed web form.

☛ PUT: Similar to POST, but used to replace an existing entity.

☛ PATCH: Similar to PUT, but used to update only certain fields within an existing entity.

☛ DELETE: Removes data from the server.

☛ TRACE: Provides a means to test what a machine along the network path receives when a request is made. As such, it simply returns what was sent.

☛ OPTIONS: Allows a client to request information about the request methods supported by a service. The relevant response header is Allow and it simply lists the supported methods. (It can also be used to request information about the request methods supported for the server where the service resides by using a * wildcard in the URI.)

☛ HEAD: Same as the GET method for a resource, but returns only the response headers (i.e., with no entity-body).

☛ CONNECT: Primarily used to establish a network connection to a resource (usually via some proxy that can be requested to forward an HTTP request as TCP and maintain the connection). Once established, the response sends a 200 status code and a "Connection Established" message.

There are several reasons why web designers should stop using tables for layouts, and adopt the use of CSS for controlling HTML layouts.

☛ It adheres to current W3C web standards and it improves accessibility of the information to a wider variety of users, using a wide variety of user agents.

☛ There are bandwidth savings as large numbers of semantically meaningless <table>, <tr> and <td> tags are removed from dozens of pages leaving fewer, but more meaningful headings, paragraphs and lists.

☛ Layout instructions are transferred into site-wide CSS stylesheets, which can be downloaded once and cached for reuse while each visitor navigates the site.

☛ If coded well, CSS makes it easy to apply global changes to the layout

☛ Web pages often have less code, and are much thinner when XHTML and CSS are used

☛ Sites may become more maintainable as the whole site can be restyled or re-branded in a single pass merely by altering the mark-up of the specific CSS, affecting every page which relies on that stylesheet.

☛ New HTML content can be added in such a way that consistent layout rules are immediately applied to it by the existing CSS without any further effort.