function di_getStyle(elem, style) {
    if (elem.currentStyle) {
        style = style.replace(/-([a-z])/g, function(s, a){ return a.toUpperCase(); });
        var value = elem.currentStyle[style];
    } else if (window.getComputedStyle) {
        var value = document.defaultView.getComputedStyle(elem, null).getPropertyValue(style);
    }
    return (value == 'auto' || value == null || value == 'medium') ? 0 : parseInt(value);
}

function di_getHeight(elementID) {
    var elem = document.getElementById(elementID);
    return elem.offsetHeight;
}

function di_setHeight(elementID, height) {
    var elem = document.getElementById(elementID);
    var sub = di_getStyle(elem, "padding-top") + di_getStyle(elem, "padding-bottom") + di_getStyle(elem, "border-top-width") + di_getStyle(elem, "border-bottom-width");
    var real = height - sub;
    elem.style.height = real + "px";
}

function addLoadEvent(func){ 
    var oldonload=window.onload; 
    if(typeof window.onload!='function'){ 
        window.onload=func; 
    }else{ 
        window.onload=function(){ 
            oldonload(); 
            func(); 
        } 
    } 
} 

function equalHeightColumns() {
    var wrapper = di_getHeight("wrapper");
    var sidebar = di_getHeight("sidebar");
    
    var max = wrapper;
    if (max < sidebar) {
        max = sidebar;
    }

   di_setHeight("sidebar", max);
}

addLoadEvent(equalHeightColumns);