Jint

DOM and evaluation ​

The script-visible DOM is generated from AngleSharp's WebIDL-like metadata. Interface objects and prototype chains are installed so ordinary checks such as node instanceof Element work. window is the global object and inherits from Window.prototype.

Use SetContentAsync for supplied markup and ContentAsync for serialized HTML:

csharp
await page.SetContentAsync("<main><h1>Hello</h1></main>");
string html = await page.ContentAsync();

Evaluating JavaScript ​

csharp
string? title = await page.EvaluateAsync<string>("document.title");

EvaluateAsync converts the completion value to a CLR value on the page thread. Do not return the whole window or other cyclic object graphs; project the value you need.

A promise is not implicitly awaited by EvaluateAsync. Use EvaluateAndAwaitAsync when the completion value may be a promise:

csharp
var value = await page.EvaluateAndAwaitAsync<string>(
    "fetch('/data').then(r => r.text())");

The page loop remains available to process timers, microtasks, and network completions while the promise is pending.

WaitForAsync repeatedly evaluates a condition without blocking the loop:

csharp
await page.WaitForAsync(
    "document.querySelectorAll('.row').length >= 3",
    TimeSpan.FromSeconds(5));

An evaluation failure is treated as “not yet” while polling. If the timeout wins and the last evaluation threw, that JavaScript failure is reported instead of a bare false.