I need then x=0 it stoped, help pls and sry for bad english

Question

var x = prompt("Произвести отсчет от ");
var z = 0;
do {
ot();
} while(x>0);
function ot() {
document.write(x);
x--;
}
setInterval(ot,1000);

Answer 1

no need for a do while loop here
setInterval calls ot every 1000 ms (1 second)
the only thing you do need to do is use the id that setInterval returns so you can use it for clearInterval once the condition is met
var x = prompt("Произвести отсчет от ");
var z = 0;
interval=null;
function ot() {
document.write(x);
x--;
if(x <= 0){
// if x reached 0, stop the interval calls
clearInterval(interval);
}
}
interval = setInterval(ot,1000); // calls ot() every 1 second