function Permutation(str)
{
    if(str === null || str === "")
        return [];
    var res = [];
    var index = 0;
    
    step(str.split(""), index, res);
    
    return res.sort();
}

function step(strArr, cur, res) {
    if(cur === strArr.length-1){
        var i = 0, str = "";
        while(i < strArr.length){
            str += strArr[i++];
        }
        res.push(str);
    }
    
    for(var i = cur;i < strArr.length;i++) {
        if(strArr[i] === strArr[cur] && i !== cur)
            continue;
        swap(strArr, i, cur);
        step(strArr, cur+1, res);
        swap(strArr, i, cur);
    }
}

function swap(arr, a, b) {
    var temp = arr[a];
    arr[a] = arr[b];
    arr[b] = temp;
}