Use this tab to inspect HTTP headers.Ĭlick the Preview tab. The network activity that was happening during the first screenshotĬlick Capture Screenshots again to close the Screenshots pane.Ĭlick a resource to learn more information about it. DevTools shows you what network activity was occurring at that moment in time.įigure 13. The Screenshots pane provides thumbnails of how the page looked at various points during the loading process.Ĭlick the first thumbnail. See Simulate a slower connection if you need a reminder on how to do this. Reload the page again via the Empty Cache And Hard Reload workflow. Screenshots let you see how a page looked over time while it was loading. Note The Empty Cache And Hard Reload workflow is only available when DevTools is open. Hover over a Waterfall to see a breakdown. A graphical representation of the different stages of the request. Clicking a link in the Initiator column takes you to the source code that caused the request. The bottom resource is whatever was requested last.Įach column represents information about a resource. The top resource is usually the main HTML document. By default the resources are listed chronologically.

The Network panel logs all network activity in the Network Log.Įach row of the Network Log represents a resource. To view the network activity that a page causes: That's because DevTools only logs network activity while it's open and no network activity has occurred since you opened DevTools. DevTools docked to the bottom of the window DevTools docked to the bottom of the windowĬlick the Network tab. You might prefer to dock DevTools to the bottom of your window.įigure 4. Open DevTools by pressing Control+Shift+J or Command+Option+J (Mac). The demo in one window and this tutorial in a different window You might prefer to move the demo to a separate window.įigure 2. To get the most out of this tutorial, open up the demo and try out the features on the demo page. Start with the Audits panel because it gives you targeted suggestions on how to improve your page. There are many types of load performance issues that aren't related to network activity. If you're looking for ways to improve page load performance, don't start with the Network panel. Inspecting the properties of an individual resource, such as its HTTP headers, content, size, and so on.Making sure that resources are actually being uploaded or downloaded at all.The most common use cases for the Network panel are: In general, use the Network panel when you need to make sure that resources are being downloaded or uploaded as expected.

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