static JS js_fixedBackgroundImage(S imgURL) { if (empty(imgURL)) null; ret JS([[ var target = document.querySelector("body"); target.style.cssText = $style; ]], style := nlToSpace(replaceDollarVars([[ background-image: url($imgURL); background-attachment: fixed; background-position: center; background-repeat: no-repeat; background-size: cover; ]], +imgURL))); }