function isMaxLength(txtBox) 
{
    if (txtBox) 
    {
        return (txtBox.value.length <= 512);
    }
}

//function pulacampo(idobj, idproximo) {
//    var str = new String(document.getElementById(idobj).value);
//    var mx = new Number(document.getElementById(idobj).maxLength);

//    if (str.length == mx) {
//        document.getElementById(idproximo).focus();
//    }
//}

function pulacampo(idobj, idproximo) {
    var obj1 = document.all ? document.all[idobj] : document.getElementById ? document.getElementById(idobj) : "";
    var obj2 = document.all ? document.all[idproximo] : document.getElementById ? document.getElementById(idproximo) : "";

    var str = new String(obj1.value);
    var mx = new Number(obj1.maxLength);

    if (str.length == mx) {
        obj2.focus();
    }
}

function isMaxLength2(txtBox,size) {
    if (txtBox) {
        if (txtBox.value.length >= size) {
            txtBox.value = txtBox.value.substring(0, size-1);
        }
    }
}