四舍五入保留N位小数
<script>
function tobits(flt,n){
if(parseFloat(flt) == flt){
var t = 1+new Array(n+1).join("0");
return Math.round(flt * t) / t ;
}else{
return 0;
}
}
alert(tobits(108.3383533337,2));
alert(tobits(108.3383533337,4));
alert(tobits(108.3383533337,9));
</script>