<html>
<script>
function fahrenheitToCelcius(temp) {
return (parseFloat(temp) - 32) * (5 / 9);
}
function isNumber(value) {
return typeof (value) != "boolean" && !isNaN(value) && value.length > 0;
}
function minMaxTemp(value, min, max, unit) {
console.log("function called");
if (value.length == 0 || value == "-") return value;
if (!isNumber(value)) return value.substring(0, value.length - 1);
if (unit == 1) value = fahrenheitToCelcius(value);
if (parseFloat(value) < min)
return min;
else if (parseFloat(value) > max)
return max;
else return value;
}
</script>
<table class="center">
<tr>
<th>Setpoint</th>
<th><input id="setPoint" type="text" name="setPoint" value="4" onkeyup="this.value = minMaxTemp(this.value, -80, 150, 0)" /></th>
</tr>
</table>
</html>
Depending on whether you want to round down or round up, you can use Math.floor() or Math.ceil().
<th><input id="setPoint" type="text" name="setPoint" value="4" onkeyup="this.value = Math.floor(minMaxTemp(this.value, -80, 150, 0))" /></th>
MDN docs: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/floor
Since from your expected output it looks like you want the decimal numbers rounded down, I would recommend using JavaScript's Math.floor function to round the value down to the nearest integer
i.e.
Math.floor(3.712)
will return the value 3