Is it possible to copy a string to the system clipboard?

Question

JavaScript

var строка = "текст"             
var кнопка_копировать   //кнопка для запуска копирования
var кнопка_вставить   //кнопка для запуска вставки

there is no text selection on the page - there are only two buttons - you need to copy and paste
when you press the corresponding button to copy / paste a line of text from a variable to the system clipboard and back
as simply as possible, without libraries,
or is it fundamentally impossible?

Answer 1

clipboardData