刚写的一个用JavaScript格式化数字的函数

 1 /**  
 2  * 格式化数字  
 3  * Author : Z,Mingyu  
 4  * 参数：  
 5  *      prmNum (Number) : 要格式化的数字  
 6  *      prmPtn (String) : 格式化规则，例如：#,##0.00  
 7  *    * prmNullValue    : 当要格式化的数字为null、空或非数字时，返回的结果。默认为0  
 8  */   
 9  function formatNum(prmNum,prmPtn,prmNullValue){   
10     var nullValue = prmNullValue ? prmNullValue : 0;   
11     if(prmNum == "" || prmNum == null) return nullValue;   
12     prmNum = prmNum.replace(/\,/g,"");   
13     if(isNaN(prmNum)) return nullValue;   
14     if(prmPtn == "" || prmPtn == null) return prmNum;   
15     var ptnLen = prmPtn.length;   
16     var pointIndex = prmPtn.indexOf(".");   
17     var groupIndex = prmPtn.indexOf(",");   
18     var pointLen = (pointIndex == -1 ? 0 : ptnLen - pointIndex - 1);   
19     prmNum = parseFloat(prmNum).toFixed(pointLen) + "";   
20     if(groupIndex != -1){   
21         if(pointIndex == -1) pointIndex = ptnLen;   
22         var len = pointIndex - groupIndex - 1;   
23         var reg = new RegExp("(-?\\d+)(\\d{"+len+"})");   
24         while(reg.test(prmNum)) prmNum = prmNum.replace(reg,"$1,$2");   
25     }   
26     return prmNum;   
27 }