<script>
function round (n, d) {
n = n - 0;
d = d || 2;
var f = Math.pow(10, d);
n = Math.round(n * f) / f;
n += Math.pow(10, - (d + 1));
n += '';
return d == 0 ? n.substring(0, n.indexOf('.')) :
n.substring(0, n.indexOf('.') + d + 1);
}alert(round(12.535464646464634343,5))
</script>其中:n是要舍的数字;d是位数
function round (n, d) {
n = n - 0;
d = d || 2;
var f = Math.pow(10, d);
n = Math.round(n * f) / f;
n += Math.pow(10, - (d + 1));
n += '';
return d == 0 ? n.substring(0, n.indexOf('.')) :
n.substring(0, n.indexOf('.') + d + 1);
}alert(round(12.535464646464634343,5))
</script>其中:n是要舍的数字;d是位数
<script>
function round (n, d) {
n = n - 0;
var f = Math.pow(10, d);
n = Math.round(n * f) / f;
return n;
}alert(round(12.535464646464634343,4))
</script>