方法如下：
function getZero(num, index) {
if((parseInt(num) != 0) && (typeof num == "undefind" || num == null || num == "" || isNaN(num))) return num;
var _num = parseInt(num);
if(!index) index = 2;
if(_num != 0) {
if(_num<0){
_num = -_num;
for (var i = 1; i < parseInt(index); i++) {
if(parseInt(_num) < Math.pow(10,i)) {
_num = "0" + _num;
}
}
_num = "-"+_num;
return _num;
}
for (var i = 1; i < parseInt(index); i++) {
if(parseInt(_num) < Math.pow(10,i)) {
_num = "0" + _num;
}
}
}
return _num;
}
如有表述不准确之处，欢迎指正，欢迎补充，感谢阅读！