このようなイベントを使用して、keyup
考慮に入れる前に入力値が数値かどうかを確認できます
http://jsfiddle.net/Pqd8B/2/
// Catch all inputs key events : recalculate average
$('.td_input').keyup(function () {
// Init variables
var total = 0,
valid_labels = 0,
average;
$('.td_input').each(function () {
// Retrieve input value
// .innerHTML only retrieves the info between the HTML tags, and is
// a non-jQuery call. The jQuery version is .html(), but you want
// .val() with no parameters, which gets the current input value
var val = parseInt($(this).val(), 10);
//Test if it is a valid number with built-in isNaN() function
if (!isNaN(val)) {
valid_labels += 1;
total += val;
}
});
// Calculate the average
// Note: This is done inside the keyup handler
// When it is outside, it is only calculated once when the page loads
$('.average').val(total / valid_labels);
});