“ y未定义” Javascript AJAX

sorry i'm very new to JS, i'm trying to write some code to dynamically count the words on a page, this code is within a 'whenkeydown' function:

var text = $(this).val();

var word=text.split(" ")

    //word counter
function countWords(word, text) {
    var y = word.value; 
    var words = 0;
    a = y.replace(/\s/g, ' ');
    a = a.split(' ');
    for ( z = 0; z < a.length; z++) {
        if (a[z].length > 0)
            words++;
    }
    wordCount = words;
}

But i get an error message saying "TypeError: y is undefined" in the debugger? Thanks

word is an array, it does not have attribute value. Moreover your functions seems to accept the whole string as a parameter, not an array of words. Here is a clearer version:

function countWords(text) {
    var words = text.replace(/\s/g, ' ').split(' ');
    var wordCount = 0;
    for (var z = 0; z < words.length; z++) {
        if (words[z].length > 0)
            wordCount++;
    }

    return wordCount;
}

var text = $(this).val();
var wordCount = countWords(text);

function countWords(wordsArray) {
  var words = 0;
  try{ 
    for(k in wordsArray){
      var sa = (wordsArray[k]  ? word.value.replace(/\s/g, ' ') : '').split(' ');
      for (i in sa) if(sa[i].trim()) words++;
    }
  catch(ex){}
  return words;
}

OR:

$(this).val().match(/\S+/g).length;