格式化數字的函數

//格式化數字的函數FormatCurrency
//入參：1. srcStr->被格式化的數字
//      2. nAfterDot->小數位數
//      3. intClause->分隔位數
//調用實例:FormatCurrency('123456789','2','3') ;   return:123,456,789.00
function FormatCurrency(srcStr,nAfterDot,intClause)
{
    var flag = false;
    srcStr = srcStr + '';
    if(srcStr.indexOf('-') != -1)
    {
        srcStr = srcStr.substring(1);
        flag = true;
    }
    if(!isNaN(srcStr))
    {          
        if(intClause>0 || intClause<=srcStr.length)
        {  
            var IvarA;
            var IvarB;
            if(srcStr.indexOf('.')!=-1)
            {
                IvarA=srcStr.substr(0,srcStr.indexOf('.'));
                IvarB='0'+srcStr.substr(srcStr.indexOf('.'));
            }
            else
            {
                IvarA=srcStr;
                IvarB="";
            }
            var Icount=parseInt(IvarA.length/intClause);
            var Imod=IvarA.length%intClause;
            var newstr;
            if(Imod>0)
            {
                newstr=IvarA.substr(0,Imod)+',';
            }
            else
            {
                newstr='';
            }
             var format=',';
            for(var i=1;i<=Icount;i++)
            {              
                if(i==Icount)
                {
                    format='';
                }
                newstr+=IvarA.substr(Imod+(i-1)*intClause,intClause)+format;
            }
            var Point;
            if(IvarB=='')
            {  
                if(nAfterDot>0)
                { 
                    Point=Math.round(Math.pow(10,nAfterDot));
                    Point='0.'+Point.toString().substr(1);
                }
                else
                {
                    Point='';
                }
            }
            else
            {
                Point=Math.round(IvarB*(Math.pow(10,nAfterDot)))/Math.pow(10,nAfterDot)
            }
            newstr=newstr+Point.toString().substr(1);   
        }
    }
 if(flag)
 {
     newstr = '-' + newstr;
 }
 return newstr;
}