- document.getElementById("totcold").innerHTML =
- ((data.cold[data.cold.length - 1][1] - data.cold[0][1]) * 10);
- document.getElementById("tothot").innerHTML =
- ((data.hot[data.hot.length - 1][1] - data.hot[0][1]) * 10);
+ if (data.cold.length)
+ document.getElementById("totcold").innerHTML =
+ ((data.cold[data.cold.length - 1][1] - data.cold[0][1]) * 10);
+ else document.getElementById("totcold").innerHTML = "0";
+ if (data.hot.length)
+ document.getElementById("tothot").innerHTML =
+ ((data.hot[data.hot.length - 1][1] - data.hot[0][1]) * 10);
+ else document.getElementById("tothot").innerHTML = "0";