Convert numbers to number names, js, dictionary

Write a script that converts a number in the range [0...999] to a text corresponding to its English pronunciation. Examples:
    0 -> "Zero"
    273 -> "Two hundred seventy three"
    400 -> "Four hundred"
    501 -> "Five hundred and one"
    711 -> "Seven hundred and eleven"

function ConvertNumber() {
    var cons = document.getElementById("console");
    var numStr = document.getElementById("problem8").value;
    var dict = {
        0: "zero", 1: "one", 2: "two", 3: "three", 4: "four", 5: "five", 6: "six",
        7: "seven", 8: "eight", 9: "nine", 10: "ten", 11: "eleven", 12: "twelve", 13: "thirteen", 14: "fourteen", 15: "fifteen",
        16: "sixteen", 17: "seventeen", 18: "eighteen", 19: "nineteen", 20: "twenty", 30: "thirty", 40: "forty", 50: "fifty", 60: "sixty",
        70: "seventy", 80: "eighty", 90: "ninety"
    };
    var result = "";
    if (numStr.length == 3) {
        result = dict[numStr[0]] + " hundred";
        numStr = numStr.substring(1);
        if (numStr == "00") {
            cons.innerHTML = result;
            return;
        }
    }
    if (!ExistInDictionary(numStr, dict, cons, result))
    {
        //common case
        if (result.length > 0) {
            cons.innerHTML = result + " " + dict[(parseInt(numStr[0]) * 10).toString()] +" "+ dict[numStr[1]];
        } else {
            cons.innerHTML = dict[(parseInt(numStr[0]) * 10).toString()] + " " + dict[numStr[1]];
        }
    }
}
function ExistInDictionary(numStr,dict,cons,result)
{
    if (numStr in dict) {
        if (result.length > 0) {
            cons.innerHTML = result + " and " + dict[numStr];
        } else {
            cons.innerHTML = dict[numStr];
        }
        return true;
    }
}