I have to do equal height elements in layouts with support for older IE all the time! Here's my approach: http://codepen.io/tomhodgins/pen/pjmKNj
onload = onresize = function(){
var cols = document.querySelectorAll('[data-col]'),
encountered = []
for (i=0;i<cols.length;i++){
var attr = cols[i].getAttribute('data-col')
if (encountered.indexOf(attr) == -1){
encountered.push(attr)
}
}
for (set=0;set<encountered.length;set++){
var col = document.querySelectorAll('[data-col="'+encountered[set]+'"]'),
group = []
for (i=0;i<col.length;i++){
col[i].style.height = 'auto'
group.push(col[i].scrollHeight)
}
for (i=0;i<col.length;i++){
col[i].style.height = Math.max.apply(Math,group)+'px'
}
}
}