Javascript 解析,格式化日期

来源：http://gwbasic.iteye.com

/*  
  将String类型解析为Date类型.  
  parseDate('2006-1-1') return new Date(2006,0,1)  
  parseDate(' 2006-1-1 ') return new Date(2006,0,1)  
  parseDate('2006-1-1 15:14:16') return new Date(2006,0,1,15,14,16)  
  parseDate(' 2006-1-1 15:14:16 ') return new Date(2006,0,1,15,14,16);  
  parseDate('2006-1-1 15:14:16.254') return new Date(2006,0,1,15,14,16,254)  
  parseDate(' 2006-1-1 15:14:16.254 ') return new Date(2006,0,1,15,14,16,254)  
  parseDate('不正确的格式') retrun null  
*/  
function parseDate(str){   
  if(typeof str == 'string'){   
    var results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) *$/);   
    if(results && results.length>3)   
      return new Date(parseInt(results[1]),parseInt(results[2]) -1,parseInt(results[3]));    
    results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) +(\d{1,2}):(\d{1,2}):(\d{1,2}) *$/);   
    if(results && results.length>6)   
      return new Date(parseInt(results[1]),parseInt(results[2]) -1,parseInt(results[3]),parseInt(results[4]),parseInt(results[5]),parseInt(results[6]));    
    results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) +(\d{1,2}):(\d{1,2}):(\d{1,2})\.(\d{1,9}) *$/);   
    if(results && results.length>7)   
      return new Date(parseInt(results[1]),parseInt(results[2]) -1,parseInt(results[3]),parseInt(results[4]),parseInt(results[5]),parseInt(results[6]),parseInt(results[7]));    
  }   
  return null;   
}   
  
/*  
  将Date/String类型,解析为String类型.  
  传入String类型,则先解析为Date类型  
  不正确的Date,返回 ''  
  如果时间部分为0,则忽略,只返回日期部分.  
*/  
function formatDate(v){   
  if(typeof v == 'string') v = parseDate(v);   
  if(v instanceof Date){   
    var y = v.getFullYear();   
    var m = v.getMonth() + 1;   
    var d = v.getDate();   
    var h = v.getHours();   
    var i = v.getMinutes();   
    var s = v.getSeconds();   
    var ms = v.getMilliseconds();      
    if(ms>0) return y + '-' + m + '-' + d + ' ' + h + ':' + i + ':' + s + '.' + ms;   
    if(h>0 || i>0 || s>0) return y + '-' + m + '-' + d + ' ' + h + ':' + i + ':' + s;   
    return y + '-' + m + '-' + d;   
  }   
  return '';   
}  

/*
  将String类型解析为Date类型.
  parseDate('2006-1-1') return new Date(2006,0,1)
  parseDate(' 2006-1-1 ') return new Date(2006,0,1)
  parseDate('2006-1-1 15:14:16') return new Date(2006,0,1,15,14,16)
  parseDate(' 2006-1-1 15:14:16 ') return new Date(2006,0,1,15,14,16);
  parseDate('2006-1-1 15:14:16.254') return new Date(2006,0,1,15,14,16,254)
  parseDate(' 2006-1-1 15:14:16.254 ') return new Date(2006,0,1,15,14,16,254)
  parseDate('不正确的格式') retrun null
*/
function parseDate(str){
  if(typeof str == 'string'){
    var results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) *$/);
    if(results && results.length>3)
      return new Date(parseInt(results[1]),parseInt(results[2]) -1,parseInt(results[3])); 
    results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) +(\d{1,2}):(\d{1,2}):(\d{1,2}) *$/);
    if(results && results.length>6)
      return new Date(parseInt(results[1]),parseInt(results[2]) -1,parseInt(results[3]),parseInt(results[4]),parseInt(results[5]),parseInt(results[6])); 
    results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) +(\d{1,2}):(\d{1,2}):(\d{1,2})\.(\d{1,9}) *$/);
    if(results && results.length>7)
      return new Date(parseInt(results[1]),parseInt(results[2]) -1,parseInt(results[3]),parseInt(results[4]),parseInt(results[5]),parseInt(results[6]),parseInt(results[7])); 
  }
  return null;
}

/*
  将Date/String类型,解析为String类型.
  传入String类型,则先解析为Date类型
  不正确的Date,返回 ''
  如果时间部分为0,则忽略,只返回日期部分.
*/
function formatDate(v){
  if(typeof v == 'string') v = parseDate(v);
  if(v instanceof Date){
    var y = v.getFullYear();
    var m = v.getMonth() + 1;
    var d = v.getDate();
    var h = v.getHours();
    var i = v.getMinutes();
    var s = v.getSeconds();
    var ms = v.getMilliseconds();   
    if(ms>0) return y + '-' + m + '-' + d + ' ' + h + ':' + i + ':' + s + '.' + ms;
    if(h>0 || i>0 || s>0) return y + '-' + m + '-' + d + ' ' + h + ':' + i + ':' + s;
    return y + '-' + m + '-' + d;
  }
  return '';
}