if I have this:
function add(){
var val = document.getElementById("item").value;
document.getElementById("items").value = val;
}<table>
<input type="text" name="item" id="item" value="" >
<input type="hidden" name="items[]" id="items[]" value="" >
<button onclick="add()" type="button"> Add</button>
</table>so I just want add some values to input items[], It's possible? in javascript I use push(), but in this case I don't know what to do.
You should create a new items[] element for each value that you're adding. Then the middleware on the server should automatically create an array with all these values.
function add(){
var val = document.getElementById("item").value;
var item = document.createElement("input");
item.type = "hidden";
item.name = "items[]";
item.value = val;
document.getElementById("form").appendChild(item);
}<form id="form">
<input type="text" name="item" id="item" value="">
<button onclick="add()" type="button"> Add</button>
</form>