//把值按3个为一组加入,号,小数点内保留两位
为txtprojectcost增加keyup和blur方法
   $("#txtprojectcost").keyup(function(){                             
                if(isNaN(this.value.replaceAll(",",""))){
                  this.value = this.value.replaceAll(",","").replace(/[^\d.]/g, "");

                  this.value=this.value.replaceAll(",","").replace(/^\./g, "");//首位不能为.
                  this.value=this.value.replaceAll(",","").replace(/^00/g, "");//首两位不能为00
}
             
            }).blur(function(){
                jiSuan(this);
            });

  function jiSuan(obj)
 {
  var newStr = "";
  var count = 0;

obj.value=obj.value.replaceAll(",","");
if(obj.value=="") return;
  if(obj.value.indexOf(".")==-1)
  {
   for(var i=obj.value.length-1;i>=0;i--)
   {
    if(count % 3 == 0 && count != 0)
    {
     newStr = obj.value.charAt(i) + "," + newStr;
    }
    else
    {
     newStr = obj.value.charAt(i) + newStr;
    }
    count++;
   }
   obj.value = newStr + ".00";
  }
  else
  {
      for(var i=obj.value.indexOf(".")-1;i>=0;i--)
   {
    if(count % 3 == 0 && count != 0)
    {
     newStr = obj.value.charAt(i) + "," + newStr;
    }
    else
    {
     newStr = obj.value.charAt(i) + newStr;
    }
    count++;
   }

   obj.value = newStr + (obj.value + "00").substr((obj.value + "00").indexOf("."),3);
  }

 }
由于给值加入逗号后正则判断会认为值不符合，所以需要替换到字符串内所有的,号,AFindText要替换掉得字符，ARepText 替换为
 String.prototype.replaceAll = stringReplaceAll;
       function stringReplaceAll(AFindText,ARepText){
 
        var st='/'+AFindText+"/gi";
    
        return  this.replace(eval("/"+AFindText+"/ig"),ARepText);
    }