Javascript/JQuery - How to get number of specific child elements

Question

I wish to get the number of all TR elements that have a input element in them somewhere. How should I proceed ?

Html :

<tbody> <tr> <td>Ignore this item 1</td> </tr> <tr> <td>Ignore this item 2</td> </tr> <tr> <td><input blablabla>... Include this TR...</td> </tr> </tbody>

Thanks!

Answer 1

$('tr:has(input)').length