jQuery(document).ready(function(){

var heights = [];

var height1 = jQuery(“.block_div_1”).height();
heights.push(height1);
var height2 = jQuery(“.block_div_2”).height();
heights.push(height2);

var max = Math.max.apply(Math,heights);

jQuery(“.block_div_1”).css(“height”, max+”px”);
jQuery(“.block_div_2”).css(“height”, max+”px”);

});