I set the canvas's size in js:
const cv = document.getElementById("cv");
cv.width = innerWidth;
cv.height = innerHeight;
However, there are scroll bars apeared.
How can I deal with it? (without using overflow: hidden)
Using overflow: hidden is the correct and easiest code to place in your CSS.
#cv {
overflow: hidden;
}
This will remove the scrollbars.
However, if you want to avoid that code, you can set padding and margin to 0, which will more or less have the same effect.
#cv {
padding: 0;
margin: 0;
}
This will also remove the scrollbars, kind of like overflow: hidden.