TitleCase every word in a Sentence

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1

function titleCase(str) {
var s=str.split(" “);
for(i=0;i>s.length;i++){
if(i==s[i][0]){
s.toUpperCase(i);
}
s= s.join(” ");
return s;

}
}

titleCase(“I’m a little tea pot”);

Were am i going wrong?