in JavaScript, the typical way to round a number to N decimal places is something like:

```
function round_number(num, dec) {
return Math.round(num * Math.pow(10, dec)) / Math.pow(10, dec);
}
```

However this approach will round to a *maximum* of N decimal places while I want to *always* round to N decimal places. For example "2.0" would be rounded to "2".

Any ideas?