JS转换数字时间

Date.prototype.format = function (format) {
    /**　时间格式
     * format="yyyy-MM-dd hh:mm:ss";　
     */
    var o = {
        "M+": this.getMonth() + 1,
        "d+": this.getDate(),
        "h+": this.getHours(),
        "m+": this.getMinutes(),
        "s+": this.getSeconds(),
        "q+": Math.floor((this.getMonth() + 3) / 3),
        "S": this.getMilliseconds()
    }
    if (/(y+)/.test(format)) {
        format = format.replace(RegExp.$1, (this.getFullYear() + "")
            .substr(4 - RegExp.$1.length));
    }
    for (var k in o) {
        if (new RegExp("(" + k + ")").test(format)) {
            format = format.replace(RegExp.$1,
                RegExp.$1.length == 1 ? o[k] : ("00" + o[k])
                    .substr(("" + o[k]).length));
        }
    }
    return format;

}

function convert(jsonDate) {

    var date = new Date();
    date.setTime(jsonDate.time);
    return date.format("yyyy-MM-dd");
};