1// Check if an element currently exists
2if ($('#element').length) {
3
4}

1$(document).ready(function() {
2    var $myDiv = $('#DivID');
3
4    if ( $myDiv.length){
5        //you can now reuse  $myDiv here, without having to select it again.
6    }
7
8
9});

1$(function() {
2    var $button = $(".the_button");
3    alert (isStale($button));
4    $button.remove();
5    alert (isStale($button));
6});
7    
8function isStale($elem)
9{
10    return $elem.closest("body").length > 0;
11};