if (!document.getElementById) document.write('<link rel="stylesheet" type="text/css" href="https://abhilashst.github.io/css/simple-slider.css">');
if (!document.getElementById) document.write('<link rel="stylesheet" type="text/css" href="https://abhilashst.github.io/css/simple-slider-volume.css">');

if (!document.getElementById) document.write('<link rel="stylesheet" type="text/css" href="https://abhilashst.github.io/css/simple-slider.css">');

Update sliderstyle.js