js实现数字每三位加逗号的方法，摘自：http://www.jb51.net/article/60801.htm

 

function formatNum(str){  var newStr = "";  var count = 0;  if(str.indexOf(".")==-1){    for(var i=str.length-1;i>=0;i--){      if(count % 3 == 0 && count != 0){        newStr = str.charAt(i) + "," + newStr;      }else{        newStr = str.charAt(i) + newStr;      }      count++;    }    str = newStr + ".00"; //自动补小数点后两位  }  else  {    for(var i = str.indexOf(".")-1;i>=0;i--){      if(count % 3 == 0 && count != 0){        newStr = str.charAt(i) + "," + newStr;      }else{        newStr = str.charAt(i) + newStr; //逐个字符相接起来      }      count++;    }    str = newStr + (str + "00").substr((str + "00").indexOf("."),3);  }  return str;}

formatNum(

'13213.24'

);

//输出13,213.24

formatNum(

'132134.2'

); 

//输出132,134.20

formatNum(

'132134'

); 

//输出132,134.00

formatNum(

'132134.236'

); 

//输出132,134.23