// Resize class constraints
// small 500px (min) - 649px
// mid   649px       - 895px
// full              > 895px 

window.onload = setScreenClass;
window.onresize = setScreenClass;

function setScreenClass(){
    var x = document.getElementById('mls_container');
    var fmt =  x.offsetWidth;
    var cls = (fmt<=649)?'small':(fmt>649&&fmt<=895)?'mid':'full';
    document.body.className=cls;
};