数字和千位符（金额）格式的相互转换

//金额格式转化function changeFormat(num){    if((num+"").trim()==""){       return"";    }    if(String(num).indexOf(',') ==-1){        num = parseFloat(num);        num = num.toFixed(2);        num = parseFloat(num)        num = num.toLocaleString();    }else{        num=num.replace(/,/gi,'');        num = parseFloat(num);    }    return num;}