round off in javascript sample code

Posted on 2004-11-26
Last Modified: 2012-05-05

I would  like to know how to round off to 1 decimal point in javascript. Any sample code? Thanks
Question by:widiyantosg
    LVL 1

    Accepted Solution

    I don't think that there is any function built into Javascript for rounding to a specific decimial place.
    But you can use the custom function below.

    Just call this function like this:
    new_number = round_decimals( The original number, Number of decimial places )


    <script language="JavaScript" type="text/javascript">

    /* This script is Copyright (c) Paul McFedries and
    Logophilia Limited (
    Permission is granted to use this script as long as
    this Copyright notice remains in place.*/

    function round_decimals(original_number, decimals) {
        var result1 = original_number * Math.pow(10, decimals)
        var result2 = Math.round(result1)
        var result3 = result2 / Math.pow(10, decimals)
        return pad_with_zeros(result3, decimals)

    function pad_with_zeros(rounded_value, decimal_places) {

        // Convert the number to a string
        var value_string = rounded_value.toString()
        // Locate the decimal point
        var decimal_location = value_string.indexOf(".")

        // Is there a decimal point?
        if (decimal_location == -1) {
            // If no, then all decimal places will be padded with 0s
            decimal_part_length = 0
            // If decimal_places is greater than zero, tack on a decimal point
            value_string += decimal_places > 0 ? "." : ""
        else {

            // If yes, then only the extra decimal places will be padded with 0s
            decimal_part_length = value_string.length - decimal_location - 1
        // Calculate the number of decimal places that need to be padded with 0s
        var pad_total = decimal_places - decimal_part_length
        if (pad_total > 0) {
            // Pad the string with 0s
            for (var counter = 1; counter <= pad_total; counter++)
                value_string += "0"
        return value_string


    Author Comment

    ok... thanks

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