Events triggered by dynamically generated element are not captured by event handler

You need to delegate the event to the closest static ancestor element within the page (see also "Understanding Event Delegation"). This simply means, the element where you bind your event handler must already exist at the time the handler is bound, so for dynamically generated elements you must allow the event to bubble up and handle it further up.

The jQuery .on method is the way to do this (or .delegate for older versions of jQuery.)

// If version 1.7 or above

$('#modal').on('keyup', 'input', function() {
    handler = $(this).val();
    name = $(this).attr('name');
});

Or in older versions

// If version 1.6 or below

// note the selector and event are in a different order than above
$('#modal').delegate('input', 'keyup', function()
{
    handler = $(this).val();
    name = $(this).attr('name');
});

This is happening because you're adding the input element after you wired up the event. Try .on:

$('body').on('keyup', 'input', function() {
    handler = $(this).val();
    name = $(this).attr('name');
});

Using .on will make sure the keyup event is wired up to inputs that are on the page originally, as well as any that are added later dynamically.

When you dynamically change the DOM, jQuery won't attach event handlers to them. You need to use on() and delegated events

For your input items, you'll need something like:

$("<parentSelector>").on("keyup", "input", function() { 
    handler = $(this).val();
    name = $(this).attr('name');
})

Where the parentSelector is something higher in the DOM than the input element, and an element that exists at page load, maybe the form ID or something.

Function binds are made ​​in page load. To work on elements created dynamically using the function live (). Example:

$ ("p"). live ("click", function () {
    // Your function
});