Possible Duplicate:
Finding whether the element exists in whole html page
Is there any way to check for if a ID $('#ID') exists in jQuery
Ex:
$('#cart').append('<li id="456">My Product</li>');
After running append() to something like this I want to check if my ID $('#456') exists or not. If it exits I want to change the text, else I want to append a new
$(document).ready(function() {
$('#RAM,#HDD').change(function() {
var product = $(this).find("option:selected").attr("product");
$.ajax({
url: 'ajax.php',
type: 'post',
data: $(this).serialize(),
dataType: 'json',
success: function(data) {
$('#cart').empty();
$.each(data, function(index, value) {
$('#cart').append('<li id="'+product+'">'+ value['price'] +'</li>');
});
}
});
});
});