document.getElementById("volslider").value -= -step; //WORKS as intended
document.getElementById("volslider").value += step; //Takes slider to 50/100 for any step value
<input type="range" id="volslider" min="0" max="100" value="100" oninput="updateVolume(this.value)"/>
The above code produces different results although it shouldn't. Does anyone know why?