function disableSelection(target) {
    if (typeof target.onselectstart != "undefined") //IE route
        target.onselectstart = function() { return false }
    else if (typeof target.style.MozUserSelect != "undefined") //Firefox route
        target.style.MozUserSelect = "none"
    else //All other route (ie: Opera)
        target.onmousedown = function() { return false }
    target.style.cursor = "default"
}

window.onload = function() {
    disableSelection(document.getElementById("coluna_centro"));
};