$(document).ready(function() { 

var l1 = $('#l1'); var l2 = $('#l2'); var r1 = $('#r1'); var r2 = $('#r2');

if(l1.height()>r1.height()) { r1.height ( l1.height() ); } else { l1.height ( r1.height() ); }
if(l2.height()>r2.height()) { r2.height ( l2.height() ); } else { l2.height ( r2.height() ); }


});