if (x = 3) 

Actually, you assign 3 to x and always return true (not zero). What you need is

if (x === 3)

And you don’t really need the loop here. Just need to check on value

if (value == 3) 

1) You should ensure to declare the variable (var z = 0;) or you will encounter an "undefined variable" error.

2) The while loop condition is wrong, because your loop will never print 110 and 120 with z < 100. You can set while(z < 130) or while(true).

3) I also suggest you to change your break condition from z == 130 to z >= 130, so you're not going into an endless loop in case you decide to change counter increment.

4) Finally, it is a common mistake in while loops to place counter increment in wrong line. In this case when z reaches 100 it will never go on.

var z = 0;
while (z < 130){
    z+=10;

    if (z==100){
        console.log("Cannot print 100!");
        continue;
    }
    else if (z>=130){
        console.log("Cannot print after 120!");
        break;
    }
    console.log(z);
}