var iFieldLength = 0;
function autoTab(evt,sFrom,sKeyEvt,sTo){
    
    var aIgnore = new Array(0,8,9,16,17,18,37,38,39,40,46);
    var key = (evt.which)?evt.which:evt.keyCode;
    
    for(var i = aIgnore.length - 1; i >= 0; i--){
        if(aIgnore[i] == key){
            return false;            
        }
    }

    if (sKeyEvt == "down") {
        iFieldLength = obi(sFrom).value.length;       
    }else if (sKeyEvt == "up"){
        if (obi(sFrom).value.length != iFieldLength) {
            iFieldLength = obi(sFrom).value.length;
            if (iFieldLength == obi(sFrom).getAttribute('maxlength')) {
                obi(sTo).focus();
                obi(sTo).select();
            }
        }
    }
}