JavaScript之保留两位小数

         if (!isNumeric(fm.ChangeFee.value)) {
             alert("请输入正确的变更费用");
             document.getElementsByName('ChangeFee')[0].style.borderColor = "#f64f4f";
             return false;
         }

         var string = fm.ChangeFee.value.toString();
         var index = string.indexOf(".");
         if (index > -1) {
             var pointB = parseInt(string.substring(0, index));
             var pointA = parseInt(string.substring(index + 1, string.length));
             if (index > 10 || getStrByte(pointA.toString()) > 2) {
                 alert("变更费用长度限制为10位整数，2位小数");
                 document.getElementsByName('ChangeFee')[0].style.borderColor = "#f64f4f";
                 return false;
             }
         } else if (getStrByte(string) > 10) {
             alert("变更费用字符长度限制为10位整数，2位小数");
             document.getElementsByName('ChangeFee')[0].style.borderColor = "#f64f4f";
             return false;
         }

 function isNumeric(sNumer) {
     var RegChkExp = /^(\+?)(\-?)(\d+)(\.\d+)?$/;
     return RegChkExp.test(sNumer);
 }