Set hidden form field values with JavaScript but request still empty

I try to set some hidden form field values with an onclick event. Ok, after I did something like this:

document.getElementById('hidden_field').value = 123;

I can output the value with the firebug console by enteri开发者_运维技巧ng this:

alert(document.getElementById('hidden_field').value);

So the values are definitely set. But now when I submit the form, the hidden field values are still empty.

Do you have any idea whats going wrong?

Make sure your hidden field has the name attribute:

<input id="hidden_field" name="hidden_field" type="hidden" value="123" />

Inputs without a name attribute aren't sent with the request.