如何获得上个月?
alert(currentDate.getFullYear()+'-'+ (currentDate.getMonth()+1) +'-'+currentDate.getDate());

以上弹出当月年月日

我想准确弹出上个月的年月日如何做?
例现在是2007-12-18

想弹出2007-11-18

看过一些方法是在当前年月日里减30天,但这样做并不准确,当月为2时可能是28天,有些月会31天.如何做才行?



[解决办法]

JScript code

 
 Date.prototype.getDayOfMonth = function(Mm){ 
 var Feb = (this.getFullYear() % 4 == 0)?29:28; 
 var aM = new Array(31, Feb , 31, 30, 31, 30, 31, 31, 30, 31, 30, 31); 
 return (typeof Mm == 'undefined')?aM[this.getMonth()-1]:aM[Mm-1]; 
 }; 
 Date.prototype.getDateOfPreMonth = function(){ 
  
 return new Date( 
 (this.getMonth() == 0)?(this.getFullYear()-1):this.getFullYear() , 
 (this.getMonth() == 0)?11:this.getMonth() , 
 this.getDayOfMonth( 
    (this.getMonth() == 0)?11:(this.getMonth()-1)  
  <= 
    this.getDate() 
    )?this.getDate(): 
    this.getDayOfMonth( 
 (this.getMonth() == 0)?11:(this.getMonth()-1) 
  ) 
  
 ); 
 }; 
 var d = new Date().getDateOfPreMonth(); 
 alert(d);