Changing Playback of HTML5 Video

player.js

    this.isSetSpeedEnabled = function() {
        if(typeof(this.mediaElement) === 'object'
                && this.mediaElement !== null
                && typeof(this.mediaElement.playbackRate) === 'number'
                && this.mediaElement.playbackRate > 0){
            return true;
        }
        else{
            return false;
        } 
    }

    this.setSpeed = function(speed) {
        if(this.isSetSpeedEnabled()) {
            this.mediaElement.playbackRate = speed;
        }
    }

    this.getSpeed = function(speed) {
        if(this.isSetSpeedEnabled()) {
             return this.mediaElement.playbackRate;
        } else {
             return 1;
        }
    }