$("iframe").each(function(){ var ifr_source = $(this).attr('src'); var wmode = "wmode=transparent"; if(ifr_source.indexOf('?') != -1) { var getQString = ifr_source.split('?'); var oldString = getQString[1]; var newString = getQString[0]; $(this).attr('src',newString+'?'+wmode+'&'+oldString); } else $(this).attr('src',ifr_source+'?'+wmode); });