问题描述：（将阿拉伯数字转换成罗马数字）
Create a function taking a positive integer as its parameter and returning a string containing the Roman Numeral representation of that integer.
Modern Roman numerals are written by expressing each digit separately starting with the left most digit and skipping any digit with a value of zero. In Roman numerals 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC. 2008 is written as 2000=MM, 8=VIII; or MMVIII. 1666 uses each Roman symbol in descending order: MDCLXVI.
Example:
solution(1000); // should return 'M'
Help:
Symbol Value I 1 V 5 X 10 L 50 C 100 D 500 M 1,000
Remember that there can't be more than 3 identical symbols in a row.
优秀答案：
1 function solution(number){
2 // convert the number to a roman numeral
3 var roman = {M:1000,CM:900, D:500,CD:400,C:100,XC:90,L:50,XL:40,X:10,IX:9,V:5,IV:4,I:1 }
4
5 var ans = '';
6 while(number>0){
7 for(a in roman){
8 if(roman[a]<=number){ ans += a; number-=roman[a]; break;}
9
10 }
11 }
12 return ans;
13 }