Bookmarklet to quickly return the decimal version of any Roman numeral

romans.js

javascript:(function romans(){const romans={I:1,V:5,X:10,L:50,C:100,D:500,M:1000};function getDecimalFromRomanNumeral(romanNumeral){let decimal;decimal=0;for (let i=0,l=romanNumeral.length;i<l;++i) {if(romanNumeral[i+1]&&romans[romanNumeral[i]]<romans[romanNumeral[i+1]]){decimal+=romans[romanNumeral[i+1]]-romans[romanNumeral[i]];++i;}else{decimal+=romans[romanNumeral[i]];}}return decimal;}const input=prompt('Roman numerals');const result=getDecimalFromRomanNumeral(input.toUpperCase());alert(result);})();