SEO Town

Implement a cache-control header to websites with dynamic components to help the browser elicit response from web servers. Webpage design is getting richer and richer with the use of more and more images, scripts, stylesheets and flash. Loading of these pages requires several HTTP requests from browsers. A cache-control header makes webpage components cacheable. It decreases unnecessary HTTP requests and increases visibility of the pages. Using a cache, browsers lower HTTP requests in number to let web pages load at fast pace. Using Expire headers, a web server tells how long a component will take to be cached.

Using a far future Expires header involves a few downsides. Having no impact on the number of HTTP requests, it affects page views when a user makes his first visit to a website. In such cases, performance improvement of a website depends on how many times users hit the web pages of the site. A component’s filename is to be changed on using a far future Expires header.

Bandwidth speed and internet service provider of an end-user are not within the control of a development team. However, other variables are there to reduce the response times of web servers by reducing the number of HTTP requests. One of them is compression. Web clients use the Accept-Encoding header to show support for compression of HTTP requests and responses. A web server compresses the HTTP response on seeing this header in the request.

Gzip is an effective and efficient compression method. Deflate another compression format is less effective than Gzip. Gzipping reduces the volume of HTTP response by approximately 70%. About 90% of internet traffic uses browsers that support gzip. For servers, what to gzip depends on file type. Many websites gzip HTML documents. Gzipping scripts and stylesheets is also useful. Gzipping PDF and image files rather increases file size. You can compress any other file format like JSON and XML.

Putting stylesheets at the top of documents is a measure to boost the loading efficiency of websites. It is helpful for users with slower internet connections. Users want their browsers to display web pages with lots of content as soon as possible. Progress indicators like HTML page to give users visual feedback have well been researched. It improves overall experience of users. Placing stylesheets at the bottom of the document prevents progressive rendering of web pages in many browsers. As a result, the user views a blank white page. The HTML specification requires stylesheets to be placed at the peak of the page.

According to the HTTP specification, no browsers download more than two components at the same time. Scripts cause problem by blocking parallel downloads. A browser does not support any other downloads during the downloading of a script. Therefore, keeping scripts at the bottom of document is a boost to the loading capacity of websites. In some cases, moving scripts to the bottom is not easy. Scripts use document.write that makes it difficult to move to the lower portion of the page. Using deferred scripts is an alternative solution to the problem. The Defer attribute tells the browsers that the scripts do not contain document.write. It ensures loading of web pages faster and hassle-free performance of websites.

I will turn up with the third blog on this crucial issue – speeding up the performance of websites….