Do this
function key() {
$('#key li').unbind('click');
$('#key li').bind('click', function () {
console.log($(this));
});
}
or you could do
function key() {
$('#key').find('li').unbind('click');
$('#key').find('li').bind('click', function () {
console.log($(this));
});
}
I guess the second one will surely work.
Updated method
function key() {
$(document).off('click', '#but_placeholder button');
$(document).on('click', '#but_placeholder button', function () {
$('input').val($('input').val() + $(this).html());
});
}