Question

How would I run a check after a keypress function to see if an inputs value was empty so I can do another action.

For example.

    $("input[name=amount]").keypress(function() {
        $("table[name=apply]").show();
    });

I want to hide the table if the user deletes all the keystrokes.

Answer 1

$("input[name=amount]").keyup(function() {
    if (this.value == '') {
        $("table[name=apply]").hide();
    } else {
        $("table[name=apply]").show();
    }
});

You will probably want to use either the keyup or change event so the value of the text-box has changed before the event handler runs. The keypress event fires before the value of the input has changed, so for instance if the input is blank and a key is entered, the value in the event handler would still read as blank.

Here is a demo: http://jsfiddle.net/jasper/C5KPq/