Find unique characters in string - demo http://jsfiddle.net/mplungjan/YUXVF/

gistfile1.js

function find_unique_characters(string){
    unique=[];
    while(string.length>0){
        var char = string.charAt(0);
        var re = new RegExp(char,"g");
        console.log(re,char,string.match(re))
        if (string.match(re).length===1) unique.push(char);
        string=string.replace(re,"");
    }        
    return unique.join("");
}
console.log(find_unique_characters('baraban'));
console.log(find_unique_characters('anaconda'));