My simple function for Array.indexOf doesn't actually cover the overloaded version in the JS 1.6 standard, which has an additional start parameter. Updated it to this:

if(!Array.indexOf){
    Array.prototype.indexOf = function(obj, start){
        for(var i=(start||0); i<this.length; i++){
            if(this[i]==obj){
                return i;
            }
        }
    }
}

This is based on a tip here.