javascript实现(Date format)日期格式化的三个例子

// 对Date的扩展，将 Date 转化为指定格式的String  
// 月(M)、日(d)、小时(h)、分(m)、秒(s)、季度(q) 可以用 1-2 个占位符，  
// 年(y)可以用 1-4 个占位符，毫秒(S)只能用 1 个占位符(是 1-3 位的数字)  
// 例子：  
// (new Date()).Format("yyyy-MM-dd hh:mm:ss.S") ==> 2006-07-02 08:09:04.423  
// (new Date()).Format("yyyy-M-d h:m:s.S")      ==> 2006-7-2 8:9:4.18  
Date.prototype.Format = function(fmt)  
{ //author: meizz  
  var o = {  
    "M+" : this.getMonth()+1,                 //月份  
    "d+" : this.getDate(),                    //日  
    "h+" : this.getHours(),                   //小时  
    "m+" : this.getMinutes(),                 //分  
    "s+" : this.getSeconds(),                 //秒  
    "q+" : Math.floor((this.getMonth()+3)/3), //季度  
    "S"  : this.getMilliseconds()             //毫秒  
  };  
  if(/(y+)/.test(fmt))  
    fmt=fmt.replace(RegExp.$1, (this.getFullYear()+"").substr(4 - RegExp.$1.length));  
  for(var k in o)  
    if(new RegExp("("+ k +")").test(fmt))  
  fmt = fmt.replace(RegExp.$1, (RegExp.$1.length==1) ? (o[k]) : (("00"+ o[k]).substr((""+ o[k]).length)));  
  return fmt;  
}

var time1 = new Date().format("yyyy-MM-dd HH:mm:ss");    
var time2 = new Date().format("yyyy-MM-dd");   

<mce:script language="javascript" type="text/javascript"><!-- 
/**      
 * 对Date的扩展，将 Date 转化为指定格式的String      
 * 月(M)、日(d)、12小时(h)、24小时(H)、分(m)、秒(s)、周(E)、季度(q) 可以用 1-2 个占位符      
 * 年(y)可以用 1-4 个占位符，毫秒(S)只能用 1 个占位符(是 1-3 位的数字)      
 * eg:      
 * (new Date()).pattern("yyyy-MM-dd hh:mm:ss.S") ==> 2006-07-02 08:09:04.423      
 * (new Date()).pattern("yyyy-MM-dd E HH:mm:ss") ==> 2009-03-10 二 20:09:04      
 * (new Date()).pattern("yyyy-MM-dd EE hh:mm:ss") ==> 2009-03-10 周二 08:09:04      
 * (new Date()).pattern("yyyy-MM-dd EEE hh:mm:ss") ==> 2009-03-10 星期二 08:09:04      
 * (new Date()).pattern("yyyy-M-d h:m:s.S") ==> 2006-7-2 8:9:4.18      
 */         
Date.prototype.pattern=function(fmt) {          
    var o = {          
    "M+" : this.getMonth()+1, //月份          
    "d+" : this.getDate(), //日          
    "h+" : this.getHours()%12 == 0 ? 12 : this.getHours()%12, //小时          
    "H+" : this.getHours(), //小时          
    "m+" : this.getMinutes(), //分          
    "s+" : this.getSeconds(), //秒          
    "q+" : Math.floor((this.getMonth()+3)/3), //季度          
    "S" : this.getMilliseconds() //毫秒          
    };          
    var week = {          
    "0" : "/u65e5",          
    "1" : "/u4e00",          
    "2" : "/u4e8c",          
    "3" : "/u4e09",          
    "4" : "/u56db",          
    "5" : "/u4e94",          
    "6" : "/u516d"         
    };          
    if(/(y+)/.test(fmt)){          
        fmt=fmt.replace(RegExp.$1, (this.getFullYear()+"").substr(4 - RegExp.$1.length));          
    }          
    if(/(E+)/.test(fmt)){          
        fmt=fmt.replace(RegExp.$1, ((RegExp.$1.length>1) ? (RegExp.$1.length>2 ? "/u661f/u671f" : "/u5468") : "")+week[this.getDay()+""]);          
    }          
    for(var k in o){          
        if(new RegExp("("+ k +")").test(fmt)){          
            fmt = fmt.replace(RegExp.$1, (RegExp.$1.length==1) ? (o[k]) : (("00"+ o[k]).substr((""+ o[k]).length)));          
        }          
    }          
    return fmt;          
}
      
var date = new Date();       
window.alert(date.pattern("yyyy-MM-dd hh:mm:ss")); 
// --></mce:script>

Date.prototype.format = function(mask) {
    var d = this;      
    var zeroize = function (value, length) {      
        if (!length) length = 2;      
        value = String(value);      
        for (var i = 0, zeros = ''; i < (length - value.length); i++) {
            zeros += '0';      
        }      
        return zeros + value;      
    };         
      
    return mask.replace(/"[^"]*"|'[^']*'|/b(?:d{1,4}|m{1,4}|yy(?:yy)?|([hHMstT])/1?|[lLZ])/b/g, function($0) {
        switch($0) {     
            case 'd':   return d.getDate();      
            case 'dd':  return zeroize(d.getDate());      
            case 'ddd': return ['Sun','Mon','Tue','Wed','Thr','Fri','Sat'][d.getDay()];      
            case 'dddd':    return ['Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday'][d.getDay()];      
            case 'M':   return d.getMonth() + 1;      
            case 'MM':  return zeroize(d.getMonth() + 1);      
            case 'MMM': return ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'][d.getMonth()];      
            case 'MMMM':    return ['January','February','March','April','May','June','July','August','September','October','November','December'][d.getMonth()];      
            case 'yy':  return String(d.getFullYear()).substr(2);       
            case 'yyyy':    return d.getFullYear();      
            case 'h':   return d.getHours() % 12 || 12;      
            case 'hh':  return zeroize(d.getHours() % 12 || 12);      
            case 'H':   return d.getHours();      
            case 'HH':  return zeroize(d.getHours());      
            case 'm':   return d.getMinutes();    
            case 'mm':  return zeroize(d.getMinutes());      
            case 's':   return d.getSeconds();      
            case 'ss':  return zeroize(d.getSeconds());      
            case 'l':   return zeroize(d.getMilliseconds(), 3);      
            case 'L':   var m = d.getMilliseconds();      
                    if (m > 99) m = Math.round(m / 10);      
                    return zeroize(m);      
            case 'tt':  return d.getHours() < 12 ? 'am' : 'pm';      
            case 'TT':  return d.getHours() < 12 ? 'AM' : 'PM';      
            case 'Z':   return d.toUTCString().match(/[A-Z]+$/);      
            // Return quoted strings with the surrounding quotes removed      
            default:    return $0.substr(1, $0.length - 2);      
        }      
    });
};