check element exist in jquery

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

1if ($('.element').length) {
2  // there is at least one element matching the selector
3}

1if ( $( "#myDiv" ).length ) {
2 
3    $( "#myDiv" ).show();
4 
5}

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};