I have already talked about a JavaScript function that rounds To the nearest number, but this was only useful if the number needed to be to the nearest 10 (or factor of). The following function is similar, but will round the number to the nearest 5 or 10, depending which is closer.
function round5(x) { return (x % 5) >= 2.5 ? parseInt(x / 5) * 5 + 5 : parseInt(x / 5) * 5; }
Use the function like this:
alert(round5(12)); // returns 10 alert(round5(14)); // returns 15
Comments
function round5(x) { return Math.round(x / 5) * 5; }