// 方法一
function toThousands(num) {
var result = [ ], counter = 0;
num = (num || 0).toString().split('');
for (var i = num.length - 1; i >= 0; i--) {
counter++;
result.unshift(num[i]);
if (!(counter % 3) && i != 0) { result.unshift(','); }
}
return result.join('');
}
// 方法二
function toThousands(num) {
var result = '', counter = 0;
num = (num || 0).toString();
for (var i = num.length - 1; i >= 0; i--) {
counter++;
result = num.charAt(i) + result;
if (!(counter % 3) && i != 0) { result = ',' + result; }
}
return result;
}
// 方法三
function toThousands(num) {
var num = (num || 0).toString(), re = /d{3}$/, result = '';
while ( re.test(num) ) {
result = RegExp.lastMatch + result;
if (num !== RegExp.lastMatch) {
result = ',' + result;
num = RegExp.leftContext;
} else {
num = '';
break;
}
}
if (num) { result = num + result; }
return result;
}
// 方法四
function toThousands(num) {
var num = (num || 0).toString(), result = '';
while (num.length > 3) {
result = ',' + num.slice(-3) + result;
num = num.slice(0, num.length - 3);
}
if (num) { result = num + result; }
return result;
}
// 方法五
function toThousands(num) {
var num = (num || 0).toString(), temp = num.length % 3;
switch (temp) {
case 1:
num = '00' + num;
break;
case 2:
num = '0' + num;
break;
}
return num.match(/d{3}/g).join(',').replace(/^0+/, '');
}
// 方法六
function toThousands(num) {
return (num || 0).toString().replace(/(d)(?=(?:d{3})+$)/g, '$1,');
}