How do programs that turn mobile Android/ios devices into a second PC monitor work?

Question

Android

How exactly do programs like iDispey, duet make the computer think that a device connected via usb (Android, ios) is a monitor? And how is the picture displayed on this USB device?

Answer 1

They work very "simple" - a special display driver is installed in Windows, which, instead of transferring the picture to the video adapter in a real monitor, uses some of its own protocol to transfer the picture via wifi or usb.
On the side of the application on the smartphone, the reverse process occurs - the transmitted data is read and displayed on the screen of the device.
There are several implementation options for each stage.

Answer 2

we.easyelectronics.ru/electro-and-pc/interfeys-usb...

Answer 3

No, it seems to work - jsfiddle.net/gtqtkj19 It
's crooked , of course, as I showed in the example, but it depends on the url.

Answer 4

var goodId = "http://foo.bar/17/18",
    reg = /(\d).+/;

var str = reg.exec(goodId);
    str = str[0].split('/');
    
    console.log( str );
    console.log( +str[0] );