用js 转化大小写

function capitalize(string){
        var words =string.split(" ");
        for(var i=0;i<words.length;i++)
    {
        words[i]=words[i].charAt(0).toUpperCase()+words[i].slice(1);
    }
    return words.join(" ");

}
var string = "I believe I am the best";
console.log(capitalize(string));