Javascript function that rounds up to a specific ending, such as "9.99" or "8.88" from any number or any ending.

ceilEnding.js

/**
 * Does the "Math.ceil" but goes to a given ending, such as "9.99" or "8.88".
 * 
 * Example: Math.ceilEnding( 37.46, 9.99 ) returns 39.99
 * 
 * @param float number
 * @param float ending
 * @return float
 */
Math.ceilEnding = function( number, ending ) {
    var numberEnding = number.toFixed( 2 ).substr( -parseFloat( ending ).toFixed(2).length ), difference = numberEnding - ending, placeValue = Math.pow( 10, Math.floor( ending ).toString().length );

    if ( difference > 0 ) {
        return Math.round( ( number + placeValue - difference ) * 100 ) / 100;
    } else if ( difference < 0 ) {
        return Math.round( ( number - difference ) * 100 ) / 100;
    }

    return number;
};