Starting to use jQuery having read 'jQuery in Action'. Came across the following sysntax for sortable tables: $('table.sortable').each(function() { var $table = $(this); $('th', $table).each(function(column) .....
Clearly the $('th', $table).each syntax results in traversing 'th' elements that are descendants of each of the 'table.sortable' elements. I'm missing where this syntax is documented and explained.