jQuery如何获取表格总行数

var rowCount = $('#myTable tr').length; 
var rowCount = $('#myTable >tbody >tr').length; 
$("#myTable").attr('rows').length; 
var rowCount = $('table#myTable:last').index() + 1; 
//Helper function that gets a count of all the rows <TR> in a table body <TBODY> 
$.fn.rowCount = function() { 
    return $('tr', $(this).find('tbody')).length; 
}; 
 
// USAGE: 
var rowCount = $('#productTypesTable').rowCount(); 
alert(jQuery("#jtkList").find("table").eq(0).find("tr").length);