In this post of our WPO Use Case series I discuss another very important use case. Load Time Optimization is most likely the most vital use case from an end user perspective. At the same time it is also highly important from a business perspective as studies by ShopZilla or Google and Bing show that load times have immediate effects on user behavior. The higher the load, the less end users are interested in interacting with the page. Load time therefore has a direct relationship to user acceptance and also business goals.
Analyzing loading behavior
The most commonly used means to analyze loading behavior is the waterfall chat. A waterfall chart shows the sequence of downloads on a web page. This is a great help when you want to optimize the download behavior. You can easily detect typical problems like resources blocking the download of one another, whether they are downloaded from low bandwidth connections or simply huge files. This information really helps to analyze typical network problem patterns.
Another important point to know is when important content is visible on the page. This is not necessarily the first impression time. First impression time only tells us when the page is rendered the first time. This, however, does not mean that all relevant content is visible. So we might want to analyze when all relevant content is visible to the end user. There are a couple of ways to do this. The most visually-appealing way is to use webpagetest.org. The video is built from snapshots taken during rendering, which are the easiest way to understand when all relevant parts have been rendered. If you then want to dive deeper you can use the optionally recorded dynaTrace session to analyze the behavior in detail.
In case you need to automate this testing – for example in a CI environment – you can use the export feature of a tool like dynaTrace Ajax Edition. Simply copy the content of the PurePath view and paste it into an xml file (see snipped below). Then you can easily parse the file for the first drawing event after the last element that needed to be loaded and you have the exact timing when the page was loaded and visible.