JavaScript toUpperCase isn't working. Why? -

i doing simple function. turn words first-letter upper case, doesn't work, neither display errors:

function formattitle(input) {    var words = input.split(' ');    (var = 0; < words.length; i++) {      words[i][0] = words[i][0].touppercase();    };    return words.join(' ');  };    var newtitle = formattitle("all words first-letter should upper case");    document.write(newtitle);

thanks in advance.

the problem strings in javascript immutable. can't change char this.

a solution this:

words[i] = words[i][0].touppercase()+words[i].slice(1); 

but have simpler , faster code using regular expression:

return input.replace(/\b\w/g,function(b){ return b.touppercase() }) 

(here more complete uppercasing, not after spaces - if want stick spaces use replace(/(\s+|^)\w/g,function(b){ return b.touppercase() }))