JS implements a summary of how time is formatted

//Extend the format method for Date
Date.prototype.format = function (format) {
    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 getSmpFormatDate(date, isFull) {
    var pattern = "";
    if (isFull == true || isFull == undefined) {
        pattern = "yyyy-MM-dd hh:mm:ss";
    } else {
        pattern = "yyyy-MM-dd";
    }
    return getFormatDate(date, pattern);
}
  
function getSmpFormatNowDate(isFull) {
    return getSmpFormatDate(new Date(), isFull);
}
  
function getSmpFormatDateByLong(l, isFull) {
    return getSmpFormatDate(new Date(l), isFull);
}
  
function getFormatDateByLong(l, pattern) {
    return getFormatDate(new Date(l), pattern);
}
  
function getFormatDate(date, pattern) {
    if (date == undefined) {
        date = new Date();
    }
    if (pattern == undefined) {
        pattern = "yyyy-MM-dd hh:mm:ss";
    }
    return date.format(pattern);
}
//alert(getSmpFormatDate(new Date(1279849429000), true));
//alert(getSmpFormatDate(new Date(1279849429000),false));    
//alert(getSmpFormatDateByLong(1279829423000, true));
//alert(getSmpFormatDateByLong(1279829423000,false));    
//alert(getFormatDateByLong(1279829423000, "yyyy-MM"));
//alert(getFormatDate(new Date(1279829423000), "yy-MM"));
//alert(getFormatDateByLong(1279849429000, "yyyy-MM hh:mm"));