function longestWord(string) {
var str = string.split(\" \");
var longest = 0;
var word = null;
for (var i = 0; i < str.length - 1; i++) {
I find that the .map method here helps a lot (this is if you want the character count of the word, not the word itself):
function findLongestWord(str) {
var array = str.split(/\s+/);
var wordLength = array.map(function(i) {
return i.length;
});
var largest = Math.max.apply(Math, wordLength);
return largest;
}