Blind scan a fully automatic scan of all possible local IP ranges for broadcast addresses.
Targetted scan Local IP address:
an upwards scan for the local network broadcast address associated with the given IP address.
a scan for an active device at the given address.
Scan options
When a broadcast address is detected, scan the associated local network for active devices.

When an active devices is detected, scan its ports.
Request options Requests will be made using:

Browsers prevent websites from making requests to certain ports. This blacklist appears to differ between XMLHttpRequests and Image.src (e.g. RDP port 3389 can only be detected with Image.src). The accuracy/speed of these method can also differ in some browsers (e.g. Image.src is very slow/inaccurate in Chrome).

Maximum number of simultaneous requests:
Bigger values allow for faster scanning, but too many requests can make the results inaccurate (i.e. active devices and open ports may not be detected). Smaller values result in slower scans but provide more accurate results. Here's the maximum values that provide accurate results for me:
Firefox: XMLHttpRequest = 200, Image.src = 120
Chrome: XMLHttpRequest = 50, Image.src = 10
Preload images: