How to disable / readOnly CRM fields / iframes

Sometimes we need to disable all fields in CRM, so a function could help!
Also, you don't want to diable INPUT/TEXTAREA nodes, because it will become unreadble (gray #808080) if you disable it, so I prefer to set those nodes readOnly. (only INPUT and TEXTAREA support readOnly property!)

/*
setDisabled function
1. set readOnly property for INPUT/TEXTAREA nodes
2. disable other nodes
id: element's Id
ignoreNodes: nodes can be ignored
nodesDisabled: bool, true = set disable/readonly
*/

function setDisabled(id, ignoreNodes, nodesDisabled)
{
    var node, nodes;
    nodes = id.getElementsByTagName('*');
    if(!nodes)
        return;

    var i = nodes.length;
    while (i--)
    {
        node = nodes[i];
        if(node.nodeName && !(node.nodeName.toLowerCase() in ignoreNodes))
        {
            if((node.nodeName == "INPUT") || (node.nodeName == "TEXTAREA"))
            {
                node.readOnly = nodesDisabled;
            }
            else
            {
                node.disabled = nodesDisabled;
            }
        }
    }
}

/*disable/readonly fields*/
setDisabled(document.getElementById("areaForm"), {table:'', iframe:'', div:'', form:'', col:'', colgroup:'', lable:'', span:'', tbody:'', body:'', tr:'', td:''}, true);

/*disable IFRAME*/
try
{
    window.setTimeout(iframeDisabled, 3000);
}
catch(err)
{
    alert("System busy, please try again later!" + err);
    window.close();
}

function iframeDisabled()
{
    setDisabled(document.frames("IFRAME_1").document.getElementById("mnuBar1"),{}, true);
}