package main

import (
 "context"
 "log"
 "time"
    "github.com/chromedp/chromedp"
)

func main() {
 // create chrome instance
 ctx, cancel := chromedp.NewContext(
  context.Background(),
  // chromedp.WithDebugf(log.Printf),
 )
 defer cancel()

 // create a timeout
 ctx, cancel = context.WithTimeout(ctx, 15*time.Second)
 defer cancel()

 // navigate to a page, wait for an element, click
 var example string
 err := chromedp.Run(ctx,
  chromedp.Navigate(`https://pkg.go.dev/time`),
  // wait for footer element is visible (ie, page is loaded)
  chromedp.WaitVisible(`body > footer`),
  // find and click "Example" link
  chromedp.Click(`#example-After`, chromedp.NodeVisible),
  // retrieve the text of the textarea
  chromedp.Value(`#example-After textarea`, &example),
 )
 if err != nil {
  log.Fatal(err)
 }
 log.Printf("Go's time.After example:\n%s", example)
}

package main

import (
 "context"
 "log"
 "os"

 "github.com/chromedp/chromedp"
)

func main() {
 // create context
 ctx, cancel := chromedp.NewContext(
  context.Background(),
  // chromedp.WithDebugf(log.Printf),
 )
 defer cancel()

 // capture screenshot of an element
 var buf []byte
 if err := chromedp.Run(ctx, elementScreenshot(`https://pkg.go.dev/`, `img.Homepage-logo`, &buf)); err != nil {
  log.Fatal(err)
 }
 if err := os.WriteFile("elementScreenshot.png", buf, 0o644); err != nil {
  log.Fatal(err)
 }

 // capture entire browser viewport, returning png with quality=90
 if err := chromedp.Run(ctx, fullScreenshot(`https://brank.as/`, 90, &buf)); err != nil {
  log.Fatal(err)
 }
 if err := os.WriteFile("fullScreenshot.png", buf, 0o644); err != nil {
  log.Fatal(err)
 }

 log.Printf("wrote elementScreenshot.png and fullScreenshot.png")
}

// elementScreenshot takes a screenshot of a specific element.
func elementScreenshot(urlstr, sel string, res *[]byte) chromedp.Tasks {
 return chromedp.Tasks{
  chromedp.Navigate(urlstr),
  chromedp.Screenshot(sel, res, chromedp.NodeVisible),
 }
}

// fullScreenshot takes a screenshot of the entire browser viewport.
//
// Note: chromedp.FullScreenshot overrides the device's emulation settings. Use
// device.Reset to reset the emulation and viewport settings.
func fullScreenshot(urlstr string, quality int, res *[]byte) chromedp.Tasks {
 return chromedp.Tasks{
  chromedp.Navigate(urlstr),
  chromedp.FullScreenshot(res, quality),
 }
}