Prompt for 5 words then display longest word javascript

Question

I am trying to prompt for a 5 words then separate the words to find the longest word then display the longest word using java script. I am able to get anything to work, it wont even prompt for the words.

function longestWord(string) {
    var word = prompt("Enter a string of at least 5 words separated by spaces:") ;
    var str = string.split(" ");
    var longest = 0;
    str.forEach(function(str) {
        if (longest < str.length) {
            longest = str.length;
            word = str;
        }
    });
    return word;
    document.write("The longest word is " +word+ ".") ;
}
longestWord(string)

Answer 1

You are calling longestWord with string as a parameter, which is undefined.

<script>
function longestWord() {
    string = prompt("Enter a string of at least 5 words separated by spaces:") ;
    var str = string.split(" ");
    var longest = 0;
    str.forEach(function(str) {
        if (longest < str.length) {
            longest = str.length;
            word = str;
        }
    });
    document.write("The longest word is " +word+ ".") ;
}
longestWord();
</script>