复制代码 代码如下:
function commafy() {
var num = document.getelementbyid(numa).value;
//1.先去除空格,判断是否空值和非数
num = num + ;
num = num.replace(/[ ]/g, );
if (num == ) {
alert(空值，结束);
return;
}
if (isnan(num)) {
alert(非数，结束);
return;
}
//2.针对是否有小数点，分情况处理
var index = num.indexof(.);
if (index==-1) {//无小数点
var reg = /(-?\d+)(\d{3})/;
while (reg.test(num)) {
num = num.replace(reg, $1,$2);
}
} else {
var intpart = num.substring(0, index);
var pointpart = num.substring(index + 1, num.length);
var reg = /(-?\d+)(\d{3})/;
while (reg.test(intpart)) {
intpart = intpart.replace(reg, $1,$2);
}
num = intpart +.+ pointpart;
}
return alert(num);
}