Good article i have read on Analysing the Front End performance of any web application. The Key points are .....
SCORN stands for the following:
Size -- Caching -- Order -- Response codes -- Number
Below is the brief explanation of each of the above parameters.
Size: When it comes to website performance, smaller is better. Whether it's a graphic, a script or the base HTML page, it has to get from the server to client at least once, and that trip is bound to take less time when there is less information to transmit. Specifically look for uncompressed graphics and media, object or code duplication, script and styles living outside of the base HTML, and code "minification."
Caching: Any page or object that users will view more than once is worth at least considering caching on the client side. The trick is balancing the relative speed of pages and objects being displayed from cache with the fact that objects displayed from cache may not be the most recent version. Check for Expires settings, ETags and other client-side cache controls to see if they strike a sensible balance between object load time and object freshness.
Order: Possibly the most dramatic user-perceived performance gain can be achieved by requesting component objects in the correct sequence. In most cases, the sequence of objects should be as follows:
Critical content (i.e. what the user came to the page to see)
Relevant media (i.e. graphics related to the critical content)
Incidental content (i.e. non-critical graphics, possibly advertisements)
Response codes: Checking response codes for each object can help identify requests for objects that don't actually exist, superfluous redirects and errors that aren't apparent from the browser. Each of those can cost more time than getting the object without error/redirect or eliminating the unused request entirely.
Number: For the most part, fewer is better. But depending on a user's connection speed, several smaller graphics may be faster than one large one. In the vast majority of cases, one external style sheet and one external script file will be fastest. It's worth asking questions if the number of objects impresses you as other than "fewer".
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