Important considerations | Other performance test tools

Page Detailer: Key factors

Some of the key factors that influence the time to load a Web page in a browser are:

• Page size

• Number, complexity, and size of items embedded in the page

• Number of servers that need to be accessed to retrieve all elements, and their location and network connectivity

• Use of SSL (This introduces an extra overhead.)

The Page Detailer will help you to identify when one of these problems is affecting some or all of your application. It will also help to identify problems such as broken links and server timeouts.

Some of the strategies that can be used to improve performance and resolve problems you have identified include:

• Minimize the number of embedded objects. Avoid the excessive use of images in particular. In cases where there is a standard header, footer, or side menu on every screen, consider the use of frames so that common elements do not have to be downloaded every time.

• The browser will typically retrieve multiple items in parallel, in the order in which they appear in the HTML page that it receives. Hence, sequencing of the items so that downloads for larger objects are started early can reduce the total time required to display the page, and avoid the user having to wait for a long time for the last elements to be retrieved.

• Ensure that caching is being used effectively. Often the same images are used multiple times on the same page. If there are two references to the same image in close proximity to each other in the HTML source, the browser may encounter the second reference before the HTTP request that was initiated to download the first reference has been completed. In this case the browser may issue another request to retrieve the image again. This can be avoided by pre-loading frequently used images multiple times early, or by structuring the generated pages so that such URLs do not appear consecutively.

• Minimize the use of SSL where possible. For example, some content such as images may not need to be secured even though the application as a whole needs to be secure.

• Try to avoid switching the user to an alias server name during the page load. This will help the browser to reduce the lookup time and possibly avoid a new connection.

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