Reading a page

The accessibility tree

Console.Write(await page.SnapshotAsync(new AxSnapshotOptions { Interactive = true, Selector = "main" }));

- heading "Fixture shop" [level=1]
- textbox "Search"
- checkbox "Only in stock" [checked=true]
- combobox "Sort" [expanded=false]: Name
  - option "Price"
  - option "Name" [selected]
- button "Go"
- button "Disabled" [disabled]
- heading "Section two" [level=2]

The tree prints as agent-browser's snapshot does, without refs: - role "name" [states]: value, two spaces per level. Ignored nodes and unnamed generic nodes are replaced by their children. States print in a fixed order: level, checked, pressed, expanded as name=value; selected, disabled and required when true.

`AxSnapshotOptions`	Journey
`Interactive`	`-i`	controls, headings and named landmarks only
`Compact`	`-c`	drop list markers, line breaks, and nodes with no name, value, state or children
`Urls`	`-u`	print link targets as `url=…`
`Depth`	`-d <n>`	levels below the top
`Selector`	`-s <sel>`	only the first matching element's subtree

page.AccessibilityTreeAsync() returns the nodes instead of text.

Console and errors

A page collects console messages and uncaught errors from the moment it is created.

foreach (var message in page.ConsoleMessages) Console.WriteLine(message);
foreach (var error in page.Errors) Console.WriteLine(error);
page.ClearConsole();
page.ClearErrors();

[warn] Low stock
TypeError: x is undefined (http://…/app.js:12:5)

Chrome reports an unhandled promise rejection a little after the task that caused it, so read errors after a short wait rather than straight after open.

Screenshots

byte[] viewport = await page.ScreenshotAsync();
byte[] whole = await page.ScreenshotAsync(fullPage: true);
byte[] box = await page.Css("#basket").ScreenshotAsync();

PNG only. Screenshots are files, not checkpoints: pixels differ with fonts, anti-aliasing and GPU, so a journey's screenshot writes into the artifacts folder and the transcript does not mention it. Headless Chrome's default viewport is 756×469; set one with SetViewportAsync (the CLI uses 1280×720).