//  Handing to remember for looking through a subset of dom elements..

//  The first one loops through to find any dom ID's STARTING WITH '_content'
//  (in this case we are hiding the selected elements)

$("div[id^='_content']").each(function() {
    $(this).hide();
});

//  Next one selects ID's that CONTAIN the text '_content', i.e. mydiv_content

$("div[id*='_content']").each(function() {
    $(this).hide();
});