Read the docs: you don't need to do what you're doing.
Simply use the noResults
option.
Their example:
$('input#search').quicksearch('table tbody tr', {
'delay': 100,
'selector': 'th',
'stripeRows': ['odd', 'even'],
'loader': 'span.loading',
'noResults': 'tr#noresults',
.......
looks like you would want 'noResults': '#noContent'