JQuery filter method .filter( )

The JQuery .filter( ) method is used to select a list of objects that match the applied filter. Filters can be applied whether using selector expressions or JQuery functions:

.find (Selector Expression):

Applying the fitler $('tr').find( ' : odd') on the following HTML snippet
<tr> item 1 </tr>
<tr> item 2 </tr>
<tr> item 3 </tr>
<tr> item 4 </tr>
<tr> item 5 </tr>
<tr> item 6 </tr>

will return item 2, item 4, item 6

for more about the JQuery Seletor expressions take a look on my post JQuery Selector Expressions Demystified

.find (Function):

Applies the specified function on each item and return only those that the function evaluates to true upon.

Applying the filter expression $('tr').find(function(index) { return index == 1;}) will return the second item with index 1.