javascript - Give element id numbers then insert one at end -

i have changing number of divs , need specific div go @ end.... i'd somehow count number of divs using javascript or jquery, , insert specific div @ end... example

<div class="message" id="1">  <div class="message" id="2">....  <div class="message" id="88"> 

then need final div number , add 1 gets inserted @ end

<div class="message" id="89"> 

how accomplished?

var lastid = $('div.message').last().attr('id'); $('div.message').last().parent().append('<div class="message" id="' + lastid + 1 + '">');